I'm a slow typer-- while I was banging away Dave beat me to it, but here it is better late than never..
Hey Riverbilly looks like you're having fun tying.
Sure you're 5 weight would be great for perfect for throwing a size 16--
Generally a 5 weight will easily throw flies size 6 or 8 down to as small as they make 'em, size 32. You can throw larger stuff too, but large wind resistant flies and poppers and/or big heavily weighted stuff would usually be easier to throw with a heavier weight fly rod.
A 5x tippet would be about right for the size 16 fly-- Generally I use a knotless tapered monofilament leader about as long as my rod (9' long) and add a short (about 2') section of tippet to the end of the leader-- that way you can change flies without chopping up your tapered leader too much.
Here's a link to some info and a chart from our Fly Fishing Gear FAQ forum that might help: http://www.theflyfishingforum.com/fo...-do-i-use.html
There area couple different guidelines you can use to match fly size with tippet size-- the one that's easiest to remeber is hook size divided by 3 = tippet size--- so for a fly on a size 12 hook, size 12 / 3 = 4X tippet.
for your size 16, divided by 3 = 5X (since 5 is the closest to 5.333333)
That said, if all you have is 4x or 6x that doesn't mean you have to pack up and go home-- these are just guidelines