Here's what I've found with my board making journey:

Always take your time - use the slow cure epoxy.  It seems like you would have plenty of time even with the faster cure stuff, but there are so many times when putting things in the vacuum bag where things just aren't working well.  It takes more time than one would think to get things working properly.

ALWAYS wrap the whole mold/board in painters plastic.  I've already wrecked a few bags trying to skimp and not wrap the whole board.  Although epoxy isn't supposed to stick to the vacuum bag, it does, and I've ruined 2 bags from ripping holes in them trying to get the board out after the stupid mistake.

Angled sides - not good. If the sides "catch" on the water, you'll fall over on your side. Angled front and rear, good.

Material behind the t-bar not needed. My boards are chopped off a few inches behind the t-bar and angled up.

Thick middle "runner" on the front bottom section of the board is a good thing. Mine is about an inch deeper at the front of the board than a normal SkySki board. Seems to help with some splashing, and also bouyancy/landings, tracking, etc. Not a huge improvement, but noticeable.

I gave up trying to get c/f thick enough without stringers inside the board. I now use stringers in my boards for strength. You can go the Steele method and make the rear of the board solid c/f-Kevlar in which case you probably wouldn't need stringers.  My stringers go up to the foot bindings.

Honeycomb is impossible to keep water out of. Great for light boards and strength, but over time, boards develop small leaks, and will end up trapping water and weighing more.

3lb expanding foam is as low as you can go otherwise the vacuum bag will crush the foam when laying up the top layers of the board.  Even with 3lb, you have to back off the pressure on the first layer of c/f.

I use crumpled up fiberglass/epoxy in the foot binding areas now to keep the screws from pulling out - tried plastic -worked great but too heavy. I've embedded the footstays, etc into the board, but won't do that any more. I prefer the screws and binding rails so that you can swap out parts if need be.

The ONLY epoxy I will use any more is Aeropoxy. More expensive, but MUCH better to work with (and supposedly stronger)

I use round headed 3/8" bolts to secure the tower to the boards (bolts come up through the bottom). I don't notice a difference with the bolt heads sticking down a bit below the bottom surface of the board.

Take your time making a board. The first one you are very excited to complete - but the more time you take, the better the board will turn out. I can do a board in a weekend if I HAVE to, but I usually take 3 or 4 weekends now to finish one.

Reinforce the heck out of the center bottom section in front of the t-bar. I never realized you had to do that until I was cracking boards from getting on them on the rear platform. Now I don't have that issue after beefing up that area. (if you never get on the board on the back swim platform, it doesn't matter)

 I now use kevlar (6" tape rolls) to help keep things together and keep things from cracking.  I also wrap it around the sides before the final layers to make sure the edges of the board don't develop cracks.

Don't try to embed graphics into the board. Just use stickers after the fact.  I've tried a few different things - printed rice paper, cutting fiberglass in shapes, using cloth with printed graphics.  I keep coming back to the c/f look with stickers.

Hopefully that helps those who are thinking about getting into this. With all that said, I am still EXTREMELY happy that I decided to take on the carbon fiber board making project. I've learned what a difference a few lbs can make in the right area of the board. And now I can't live without it!  Plus they last much longer than a fiberglass board.  The amount of flex in a fiberglass board at takeoff and landings is crazy.  Especially after you've ridden a c/f board for a year or two.