I think for heavy and large flies I would go with a skagit head as I think its forgiving to a novice and is easiest to cast. But what head or sink tip. Should I be using a running line and if so are there difference. The rivers are small so maybe 50 feet to 100 feet cast.
The short head will definitely be the easiest way to enter the casting experience. When it comes to tips I'm guessing a 9 weight will call for a line weighing in the vicinity of 725 to 750 grains depending on the particular rods action. With a line of that weight you may be able to carry ten feet of T-11 or perhaps T-14, but may want to keep fly weight down until you develop your timing and stroke power to handle the line and tip.
[Edit] The most important thing to pay attention to is where the fly is at before you try to execute any cast with any line. It may be beneficial to use your cutters and snip the fly at the bend of the hook during practice. This will be a totally different experience in casting and knowing where that fly is at prior to a cast is the key to trouble free (read injury free) days on the water.
With that inserted I feel better.
I would suggest that you spend as much time as possible learning to cast with just the floating head and leader. This will provide the best chance for an easy entry into understanding the mechanics of the casting, anchor, timing and the like. When you move on to the sink tip and a weighted fly this will change everything. It will force you to speed up the casting strokes and may present the need for you to develop a higher rotation into the D loop position to raise the line as much as the head length will allow.
Once you have become used to the casting with just a floating line you will probably find that you are using rather compressed motions and keeping the rod rather low as you move into D loop and forward stroke steps. The sink tip and weighted fly will change the dynamics greatly. The timing must speed up because that tip and fly are going to sink as designed to do. This sinking while your line is in the 'anchor' position will result in 'stuck casts' unless you make adjustments to timing and height of the strokes and rod during the cast.
When a cast is 'stuck' the whole thing collapses rather quickly and goes nowhere. This problem is addressed by elevating the rod tip as you rotate into and out of the D loop position. I myself tend to elevate during the rotation and then lower the rod as I make the forward cast stroke. I also tend to make that forward stroke with a short but fast / powerful motion. The lift you put into the rod when using a weighted line and fly are what helps raise the tip and fly to just under the surface as you prepare to make the final delivery stroke. Often times my entire head is already off the water as I reach this point but the leader / sink tip and fly are what are providing the anchor and allowing the rod to fully load.
If you are casting either the floating line alone or the line with the sink tip and you hear a very audible 'poof' and the cast tends to start but quickly collapse this means your rod was too high and you had all the line out of the water prior to the forward stroke. The poof is the sound of the fly exxiting the surface but because there was no sustained anchor the rod did not load. That did not load thing is what caused a badly anchored cast to fail.
So there you have 2 situations, in one the anchor was stuck (too deep) and the line and rod even when both were working for the cast were unable to tear the tip out of the water. In the other case we were too quick or too high with the rod (or both) and there was no anchoring action to provide load at all.
While all of that may sound confusing it actually is not. The Spey style cast is a simple matter of the angler not rushing his or her development. Take time to think about what you are witnessing as you practice. If you have to advantage of having someone who would take video of you as you work at it that will be very helpful. You said you have watched many videos, if you can watch yourself you will have a basis for comparison.
At times I find it difficult to communicate all the various steps and nuances of casting to a person even when teaching them in person. Trying to write something clear enough to be understood is even more difficult. You have until fall, if you are the type who catches on quickly you'll be adequate by then. If you have difficulty then I would advise that on a trip to stick with what you know. There is also the chance that on a fishing trip, if you choose a guide or lodge service where they have casters on staff, those persons could groom you up quickly so you could enjoy swinging up some fish.
Do keep us posted as you progress,
Ard
