Hi Don,
I've been seeing some of your photo's! Nice job on the SS. On my cowling, I was able to use my fiberglass boot cowl only. The Model 4 boot cowl has 4 flat areas that provide the attachment for the ring cowl. Obviously the ring cowl is too small to use with this installation, so what I did was cut the flats out of the boot cowl and fiberglassed plugs in thier place. Then I filled and sanded, matching the contour of the existing cowl which is now my rolled leading edge. For a finishing touch I used a NAPA door edge gaurd (made of nothing but plastic) and glued it on the leading edge of the cowl to take up the gap between the collector ring and cowling. 1/4" gap is plenty to keep the plastic guard from melting.
It took some patience, and I should have done a nicer job making the gap more even and consistant. But be patient and take a little off at a time, check for fit, take a little more off if needed then check for fit. If you can use your boot cowl it should save hours of time versus laying one up from scratch.
Also, there are some folks around here after me to put on a speed ring. It would add to that old time look and not that it is out of the question, but it is a very low priority for me. The speed ring will get you a few more Kts and make the engine run cooler, but... the way it is, this engine runs pretty cool now. I didn't build this for speed, nor do I want to cover up all that beautiful machine work! So a speed ring is pretty much a mute point for me, however if you are interested I can put you in touch with a guy here that can turn one out for you rather quickly. He and his son do a real nice job on the English Wheel.
Joe