Reason your blowing head gaksets is running too much diesel judging by that video on the rollers.

My Skoda pickup is running a 1.6 VW block and 1.9 head, with the KKK K24 Turbo, wastegate completely blocked off and I am controlling boost by diesel. Basically you want a little smoke as it comes on boost which clears to a light haze after that. You are causing huge EGT's with that much un-burned diesel and blowing your gasket.

I run 21psi on the larger K24 and never had any problems. Diesel's are great for daily driving.