BSA handlebars were a nightmare. My Thunderbolt was 100 percent stock, and after a 3/4 hour cruise I could barely feel my hands or wrists.
You're dead-on right about it being like commanding a jackhammer. I did summer construction work including jackhammers, and that's the best analogy to the BSA. IIRC it would abate as you reached 70 or 75 MPH, but then you were just begging for a speeding ticket.
I only raised my bars about 10". Didn't want the "ape-hangers," just wanted enough to ease the discomfort.
BSAs were hot-looking bikes, a little more stylistic with the forward-canted cylinder blocks. In fact, when congress forced the Brits to make drastic changes for export to the USA, they used the block from the old BSA Rocket III on their post-1975 Tridents to make room for starter motors.
They were also made to swap sides with the shift and brake pedals. Mine shifts on the right and brakes on the left, and I've been on this bike so long that I don't trust myself to react properly on a non-Brit bike in an emergency situation (which is always happening in my experience). I would be jamming down on the shift pedal, trying to stop. So once I sell this bike, I'm not going to ride anymore, unless I can find a good old Sportster with a RH shift pedal.