I would put the "rules" in reverse order:
#1 rule: If you are having fun using the scope, you will keep using it for a long time.
#2 rule: The scope that you can use easily, is the scope you will use most
#3 rule: Appeture Rules
I have an LXD75 and it's a very sturdy mount that I can lift by myself. Just be aware that it may not work straight out of the box. You might have to stuff around for a week or two

, but then it will work.