For the bottom of the cowl, I taped over the area I would be cutting with masking tape, drew lines on the tape to follow, then used a cutting tool on my dremel tool to cut just outside the lines. The used a small sanding drum to carefully finish out to the lines. The tape is used to give you a temporary surface to draw on and if you mess up you can peel it off and start over. It also will protect the finish somewhat if the tool should slip. For the glow plug hole, I just used the cutter very carefully (too small for the drum to go through).

The cutting tool I use is a 1/8 inch drill bit that cuts sideways, sort of like those roto-zip cutters, but with burrs on the side like a tile cutter. The Dremel Tile cutter is #562 and is similar to what I have. I also use Dremel #115 and Dremel #199 alot for this type of cutting....

I used the 25# tailwheel because it was in stock at the vendor I ordered from. I found out later that the 15# on was in stock at Graphtech and could be ordered directly from them. I would think the 15# would be more than sufficient fo this plane...

Richard