Everybody should have one of these hoists, I don't know how I ever got by without it. I pulled two engines and installed one the other day and my back didn't even notice. I lift the front of the tractor and remove the 4 bolts in the oil pan just sitting on my stool, you can just push down on the axle to get into the bolts over the axle. Then lower the tractor and pull the engine.
Ted, since your going to do the rail mod here are some suggestions, my same old spiel.
This Mod.
Since you have a spare oil pan mount the pan under the rail just opposite of this picture, so you can weld on the other side and hold the rails at the correct distance.
Once you weld in the cross piece and remove the oil pan you will probably find the back of the rails have pulled in just slightly. You will want the holes to line up perfectly so the engine installation goes easy. I usually use my porter power to spread the rails back but you could use a small jack.
I don't know what you want to do about the ISO mounts but here are my suggestions.
If your rails were loose you probably ruined the original rubbers.
If I can find 4 good rubbers (usually the top 4 are still okay) I will buy a set of Moog K-5252 car suspension rubbers and put the 4 good old ISO rubbers on the bottom and the 4 Moog rubbers on top like this picture.
If you don't have 4 good old ISO rubbers then buy a complete ISO rubber kit from your Cub dealer. The new kits are different than the original rubbers. When you go to tighten down the new kit only tighten it enough to keep everything in place, usually about a thread left on top of the nut. If you tighten them up too much you will get a lot of vibration.
I DON'T RECOMMEND using all Moog rubbers as you wind up with too much vibration.
Just MY .02 cents.