Thermal scope - best tradeoffs?

[2tall4economy]

I've been researching thermal scopes for night time predator hunting as well as, I suppose, some sport hunting if I'm feeling unsportsmanlike...

My budget is up to ~$4,000, which means I can't get the best of every feature, so I'm trying to decide which is the most important of these three:

30hz vs 60hz
640 vs 3xx sensor
Objective lens size

So for example (only), I can choose to get the bigger objective lens but then I might have to go with only the 3xx sensor / 30hz model.

For hunting on a walk with only occasional elevated blind work, I would think that the larger objective lens is the most important thing to spend on (longer distance), followed by hz (so I can move with it), followed by sensor resolution (since that's just making it pretty vs adding functionality).

For anyone who has one of these - is that the right way to think about it?

A lot of money to spend without testing them out but unfortunately no way to do so in my neck of the woods.