I fitted a the eyebrow Jack without removing the crank. Check it with the feeler guages like I described in the earlier post.
I'll throw this out there for what it's worth, they make rear seal kits for A-series engines, we tried them on the race 1275 motors and not had alot of success with them, I believe with the ultra compression ratios we're running may be the reason why, other people with the street applications have success with them. I believe the 948/1098 Mini Maina rear seal kit works better than the 1275, because of how the rear hub of the crank is made on the 948/1098 small journal motors. It a direct bolt on kit, it kinda expensive at $250.00, but it may be something to think about, go to
https://www.minimania.com, go to classic Mini part of the site, do a advances search for part number RIC775, and you'll find what I'm talking about.
The only time, I had any experience with a rear seal kit on a 948 was in a race motor with a dry sump oiling system, but I can say firsthand it was dry as a bone at the rear.