I expect that you will get some left tilt if everything is set up centrally . Maybe try borrowing a differant prop - no idea why but some people withthis problem on bigger boats found it helped. I'd say that unless you get the boat running flat it will be very very hard ride ( they are not the deepest of hulls !) . MOre common is the stern heavy tendancy of these boats which either trim tabs or 'fins' on the OB seem to fix.
Any pictures of said problem boat ?
Also found these
, (maybe x 3) - that may help the launching problem depending onhow fast its winched up & down the beach ? At 350 Kg you should be fine with 2 under the boat & a third being moved stern to bow etc .