wow mate you really need to stop reading the sales brochures...
the lears can go to 51 but i don't know many people who go there all the time... I have flown the encore+ and it goes to 43 no problems at all (says 45 in the book but it sucks up there) but 51 in the lear is a little bit of a push as your has drops off a fair bit....
Have you thought about chartering a couple of the options for the sectors you do a nd see how that goes?