I used a couple of 18-inch extensions and came in over the back of the transmission. It works just fine. Then when I put it back, I could use the torque wrench from there. I expected some flex from the two extensions, might affect the torque reading, but I checked it with and without extensions on the lower, easy to reach bolts, and I think the torque is close enough for bell housing bolts.
Ray
'68 280SL 4-spd Coupe