zhkent,
Excellent post. Wish you were around here to provide hands-on instruction.

Great operators aren't necessarily great teachers and you sound like both.
Would it be asking too much for you to post your thoughts on size of dozer for various tasks? I've found my 450 to be excellent at general ranch work and pond repair/renovation but very slow for building a pond much beyond 1 acre. This info might help Mercury and future purchasers of dozers.
However, I'm still of the opinion that for a DIY just starting out person, it is better to start with a relatively small dozer....and a top flight teacher. Thanks.