I use wtb kom i25 rims with specialized tyres and the tyres stay inflated with no sealant. I use one wrap of gorilla tape now but previously used one wrap of stan’s or superstar tape. I prefer the gorilla as it sticks nicely and should last several tyre changes. I’m not sure if your wtb rims have the same ust compliant groove the bead sits in but the fit is so good. I always use stan’s sealant and soapy water on the bead (not washing up liquid, simple soap bar and water).
If air is coming out the spoke holes I think you’re possibly leaking at the valve. I make a small cross then use a small round file to gently remove the tape to make a perfect clean hole with neat edges, when fitting the valve I push down on the rubber base from the inside with my thumb and screw the lock ring on tight so it’s a really good fit. I’ve been doing tubeless for many years but have absolutely no problems with this method and wtb rims are by far the best I’ve used for tubeless set up.