I didn't have trim tabs on Blue Ice & Richard B hasn't fitted them either since he's had her. (7.5m Scorp). I can't say that I ever found any real problem with leaning into the wind that couldn't be corrected by trimming in or out or rearranging the crew seating.
The 7.5M Scorp works well trimmed quite a way out out in most sea states, particularly when going 'downhill' in a following sea. She does need trimming in when punching into a head sea like most boats.
30ktsish is a good most sea state cruising speed. Any slower and she doesn't 'fly' so well. She will go a lot faster capably but 30-35kts feels like a comfortable cruising speed you can keep up for an extended period without banging the crap out of yourself and spending a fortune on fuel.
As with any boat, time and experience will enable you to get the most out of her. Beam seas or large washes are uncomfortable, perhaps because the tubes are a long way out of the water compared to other ribs. (my previous rib was a BWM DS21 where the tubes are still kissing the water when on the plane. Stable, but not so efficient!) A Scorp is a world of difference from a DS21 believe me!
Slow speed handling should be as good as any other similarly sized RIB. Certainly more susceptable to being blown around than a hard boat. Particularly if its an older model with the more bulbous bow toobs!
Anyway, I had the good fortune to relive the glory days on the solent recently during a flying visit. Happy days!