: How should I set up the forms with the large?? holes?

You might want to spend a few minutes making some small wedges. You can cut these from the ends of a few strips, or, if you ripped your own strips and have some waste (too thin, too many knots, too ugly) cut those into wedges. A taper cutting arrangement on your table saw will do the trick quickly. You cna make a jig for cutting such tapers from a 9 to 12 inch piece of 1x2 and a piece of plywood anywhere from 8 to 12 inches and 10 to 14 inches long. Rip a 1/4 to 3/8 inch thick piece off of the 1x2 and see if that slides freely in one of the grooves on the table top of your saw. If it binds, sand or plane it until it fits neatly. Tack or screw this to the underside of the plywood scrap, far enough from an edge so that the designated edge can be cut off by your saw. The exact distance will vary by saw make and model, so I can't be more specific.

Start the saw and run the plywood through, allowing the blade to cut off the excess wood. Now, anytime you slide that pywood along the groove in the saw table you'll have an accurate edge. tack or screw what ever is left of your 1x2 to the top of this piece of plywood. Put it at an angle wqual to what you want your wedges to have. You can let the end overhang, and it will be trimmed off on the first pass through the saw. Now line up a strip with the 1x2 and run the strip through the saw, cutting off a wedge. REmove the strip from the jig and cut it off to make a second wedge. Keep going until you have as many wedges as you wish.

I have a disc sander plate that I can put on my table saw. With a sheet of 100 grit paper on it I can turn 1/4 inch strips into small wedges very quickly. A belt sander, mounted securely to the workbench, will do the trick, too. With hand tools you'll take a bit longer, but a plane does a good job. For the quality that you need for this job (not a lot!) you can even do the trick with a pocket knife.

hope this helps

PGJ