Hey @Kevho thanks for reaching out. Sounds like a fun build! I currently run a full tubeless set up on my mountain bike, but I've had some experience in the past with conversion kits. It's definitely a great improvement in ride quality too. You can see an example here on Stan's No Tubes which also has a handy chart to help you match the correct kit to your existing rim width. I used this on an older bike to convert to tubeless (old Santa Cruz superlight). You'll need some type of kit like this to make your non-tubeless wheels compatible. You can also get the rim tape from us here stans rim tape
I will say- I was lucky and mine held quite well (they would loose a good amount of air over a couple days). You are correct that it is a bit hit and miss, even with conversion kits.
Hope this helps,