If it were me, I’d initially keep life simple by sticking with all 22001 dimensions except the OD.
Some (very) basic stuff assuming a 70kg engine and prop combo….Call it 700 Newtons for simplicity.
Original mount net area 790mm^2 x 4off = 3,160mm^2.
Compressive stress = 790N/3,160mm^2 = 250kPa
With a 1-1/2” OD the total bearing area increases to 4,216mm^2 or 33% more. So compressive stress decreases to 790N/4,216mm^2 = 187kPa.
By implication, the compressive strain on the mounts will also be decreased by about 1/3 and along the way, you’ll have increased the surface area to dissipate all that vibration (kinetic energy) heat into the aluminium mounting rails.
Naturally, the back-up washers will also need to be increased in diameter.
It’s pretty easy to cast urethane and there’s a bunch of videos on YouTube showing people doing it at home….Search “casting polyurethane bushings” and pour yourself a drink.
If you’re still unsure of your ability (it’s easy) then pop over to 33 Holloway Dr Bayswater and talk to Melbourne Polyurethane.