Hi woodworkers,

This is a 24 mm Plywood (B grade poplar I believe) with solid oak 24 mm edges and rotary cut veneer on both side. 
I am having endless issues with this top. Already had to strip the veneer down once because I was sold rotary cut bookmatch oak veneer sheets. (I discovered that only one face is good the other cracks with such veneers) 
The dye is waterbase aniline. 
I am using one part Poly varnish with the most decent 150 mm “varnish brush” I have found here in Portugal.
This was the 4th coat. I scuff sanded with 400 grit (I only had this probably should have gone with 300), between each coat and I am having this horrendous aspect. the last coat already had done orange skin due to my attempt at using a sheepskin imitation roller but I sanded it down. 
I diluted my poly with approximately 1/4th of PU thinner. I did nottice that it was extremely hard to apply and tacky and hard to pull??
I am tring to understand what I did wrong. Paintbrush was new, can of Poly was new (same brand of course), I blasted the top with compressor then with textile rag the top…
I am quite desperate to find a solution as the amount of time spent on this piece has already reached “Legendary”.