Re: how to pull a motor?
Did you say you had access to a crane for pulling masts? I used a hand operated mast crane (chain fall type?), at my marina to lift my Universal 5416 out. It weighs a bit less than your Yanmar, probably 400-450 lbs. I did not try to use the lifting eye(s) on the motor, instead I made up two rope slings that I threaded around the engine and trans, one under the transmission end and one at the front. I put both loops onto the chair hook, and adjusted the lengths to let me lift the rear first, and then the front which then allowed the motor to do a "controlled" swing forward and out of it's "hole" (it was controlled by me sitting on the cabin floor with my feet against the engine). Then it was just lifted up through the companionway. It sounds tricky but was pretty straightforward.
I basically reversed the process to reinstall, pushing the suspended motor back into the hole with my feet while someone operated the crane. Once I had one of the engine mounts engaged I used a short pry bar to move the motor around till the others lined up.
I have removed and installed the engine twice now with this technique and find it pretty easy to do with two people.
1980 Bristol 29.9