You started 3 separate threads, all on this same topic, so I merged them into one. When you want to update or add something to a discussion, instead of starting a completely new thread, go to the old one and click on "Reply". You can "reply" to yourself even and that'll keep the whole discussion together.
As for the mowing, I didn't have a mid-mount mower myself, but with the Bush Hog RDTH60 (60" 3-point finish mower), I've mowed grass that was over a foot tall and the tractor never bogged down. I did find out that I could go fast enough to run over some without doing a good job of cutting it, but at normal mowing speeds, 12" grass was no problem at all. And with a 5' brush hog, I've mowed Johnson Grass that was taller then the tractor with no problem.