I'm not sure I have a lot of advice since I don't have any experience in anything bigger than the 45. Not really sure what transition issues to watch for when coming down to the Lear. Don't flare too high, I guess.
The cockpit is snug, but you should be OK height-wise. The rudder pedals are adjustable and move a long distance, and the seat goes down for plenty of headroom. The seats are notorious for being uncomfortable for long legs though - something about the way they don't distribute weight well along the back of the legs. I get the most relief in cruise by raising the seat as high as I can stand it, then moving the pedals back so my legs can stretch out. The combination puts more weight onto my thighs and relieves the pressure on my tail bone. Not much storage space, and it is tight climbing in and out.
Other than that, it's a really straight forward airplane to fly. Presuming you have the BR engines, it climbs well and goes to FL410/FL430 without issue. Good performer - it will red-line at any practical altitude you can climb to, but we run 0.76 or so for most legs. Lots of computers on this plane, so many of the issues have been of the Ctrl/Alt/Del type - power down, power up, problem gone. It's a pretty clean airplane, but again I don't know how it compares to what you're used to. Not allowed to use the speed brakes and flaps at the same time, and the final flap setting is limited to 150 knots so learning how much room and time you need to get slowed down is something to be aware of. Not really difficult at all, just different than some other planes.
We only have one -45 in our fleet. We also have (4) LJ-40's and (2) LJ-70's, so I haven't spent nearly as much time in the 45 as I have the 40. Not much difference of course, except the -45 has an APU (option). )I kind of prefer the 40 with a GPU running the optional air conditioner for ground comfort, but the APU on the -45 does OK as well.)
Quite a few other guys here fly the -45 and they'll chime in with more I'm sure.