I have built carbon fiber beams at home and had them built work. I have a couple comments.

I have had problems getting vacuum bagged composites to release when using a PVC pipe for a mold. It looks like they flow under pressure. My favorite mold is cardboard, the kind you can soak in water and then just peel away. For PVC pipe mold, I make my first layer glass. If I have trouble removing it I cut it lengthwise, remove it, splice it back together, then use it for a mold. Use minimum vacuum on the first layer of Carbon. After that it's strong enough to take anything.

I have used solarcomposites's finger puzzles. They work well. I find that after vacuum bagging, they are thinner than their nominal thickness. The void fraction of the fiber also depends on how far you stretch them. Basically, the more you pull them to reduce the diameter, the bigger the void. FYI I like hand wound. My favorite is 1/2 inch wide uni.

Do not drop below the percentage of carbon in your layup design
I would suggest at least 1 layer of kevlar near the middle. The purpose is prevent crack propagation. It will also hold things together if you crack your tube. Treat it as a core for strength calculations.

Good Luck, Have fun, Work slow so you can watch your work grow.