Hey Katsfood welcome to the forum.
A lot of guys out your way use type IV or VI sinktips, but as you mentioned, it will depend on the depth of the water you fish, how deep the fish typically hold etc and you’ll be fishing a lot of different ways beach, jetties, yak, and boat. You may want the flexibility of different lines or heads if you fish a lot of different depths-- fishing gradually sloping beaches from shore, cuts and channels from your yak and deep water humps from a boat. Something like Rio’s Versi-Tip system might be a good compromise. Check in a local fly shop—these guys in Fullerton would be able to give you good advice about line choice, have a great reputation, and they’re very wired into the local SW scene near you: Fly Fishing Gear by Bob Marriott?s ? Fly Fishing Supplies and Equipment ? Fly Rods and Fishing Tackle ? Fly Tying Kits and Materials ? Fly Reels and Accessories ? Fly Fishing Trips ? Fishing Sunglasses - Fly Fishing Gifts ? Fly Fishin
For what it's worth, I have older model Sages (mostly RPLX and RPLXi) with similar actions to your rods and I tend to overline full length fly lines by 1 (a 9 weight line on an 8 weight rod). I also use Shooting Heads (SH) and over line by 2 line weights (a SH equivalent to a 10 weight in grains for an 8 weight rod.
Since you bought up the Rio Out Bound and Shooting Heads, here's some info (maybe way too much). Hope fully others will chime in too.
The Rio Outbound is essentially an integrated Shooting Head, meaning that it has a 37.5‘ shooting head and thin running line (with a fly line type coating) that is already built/connected to the head. By comparison, real shooting heads have a head that is typically 30’ long and attached with knots or loop to loop connections ( for quick changes) to a thin diameter running line that can be a couple of different types. Some running lines are special flat/oval low memory mono lines like Amnesia or specially braided mono lines made as running lines. These running lines will help get maximum distance but can be very difficult to manage since they will want to blow around and tangle on everything, and because of the thin diameter, these have a tendency to cut wet fingers. Another type of running line is essentially a thin level “fly line” with a typical fly line coating. Since it's a bit heavier and more wind resistant thn the mono or braod running lines, it will cut down on distance a bit, but it's much easier to manage. (The Rio Outbound has this type of running line built in and connected to the head). Here’s a link showing the taper and also some data on the different Rio OBs available.
Fly Lines, Fly Leaders, and Fly Fishing Accessories - Rio OutBound®
The Rio Outbound is also “over weighted” for the designated weights of the fly rods. For example the AFTMA (American Fishing Tackle Manufacturer’s Association) has guidelines for the weight in grains of the first 30 feet of fly line for different line weights.
You can see the AFTMA guidelines here:
Note that for a 6 weight it’s 160 grains (+ or – 6 grains) for the first 30 feet
for an 8 weight it’s 210 grains (+ or – 8 grains) for the first 30 feet.
From the chart in the link about the Rio Outbound (above) you’ll see that the grain weight of the 37.5’ head of:
-a 6 weight Rio OB head is 240 grains-- or 192 grains for the first 30 feet equivalent to an AFTMA heavy 7 weight line (185 grains tolerable range 177-193 grains), almost within the tolerance of the lower limit of an 8 weight line (210 grains tolerable range 202- 218 grains)
-an 8 weight Rio OB head is 330 grains—or 264 grains for the first 30 feet, equivalent to an AFTMA “9 ½” heavier than the upper limit of a 9 weight line (240 grains tolerable range from 230-250 grains) but not quite within the lower limit of a 10 weight line (280 grains tolerable range 270 to 290)
So if you go with a Rio Outbound labeled “for 6 weight rods” or “for 8 weight rods”(and you should test cast it if you can) you basically are buying a SH that is essentially 2 line weights heavier than a 6 or 8 standard fly line.
Rio also makes an Out Bound Short with a 30 foot head which is even more heavily weighted. This is essentially a Shooting Head with integrated running line.
Fly Lines, Fly Leaders, and Fly Fishing Accessories - Rio OutBound® Short
If you look at the chart for the Rio OB Short you’ll see that the weight in grains for the head of the 6 weight is 235 grains (equivalent to a 9 weight line!) and the 8 weight head has a grain weight of 315 ( almost equivalent to an 11 weight line).
By the way, the reason that folks tend to overline SHs is that you only want the SH (usually 30‘) plus only 2-4 feet of running line out side the tip when you are false casting. Any more running line out of the tip and the whole thing will collapse. The idea is to use the head to load the rod and “shoot” the lighter running line through the guides on the release.
By comparison, using a regular fly line, you can false cast with more line outside the tip—and for every additional 10 feet beyond 30 feet out of the tip the weight of the line loading the rod increases by roughly a line weight or so--- so an 8 weight line with 40 feet outside the tip is roughly equivalent to a 9 weight line, with 50 feet about a 10 weight.
For backing (not running line with a SH) I like 20lb Dacron or Micron for 9 weights and below, 30lb for 10 weights and up. I don’t like the gel spun lines too thin they have a tendency to work their way into places that they’re not supposed to go, and they can cut you to pieces—but others seem to use it without any problems.
Another thing you will want for fishing the surf is a shooting basket to hold loose line while false casting. They can be easily made out of a Rubbermaid dishpan and some shock cord or cut slits in it to wear with a dive belt.
I hope some of this made sense, but keep asking questions