After over four years of filling my DI vessels i can't believe i've not done this before (must be a very small brain wave).
After filling vessel with resin 3 quarters full as usual it has always been a pain getting the riser tube in again perfectly straight so the threads don't cross. So, the other day when i filled one of my DI's with fresh resin i then filled it up with water first- hey presto! riser tube almost straight in with no hassle & no pressure probs on innitial start up!
Just thought i'd share this with you incase anyone has had similar probs.

Tony