Hi Torbjoern.
Regarding the HUD symbology size you also need to have the correct seating position. I can see you're sitting too far behind so you'd need to move forward. Than might feel to you like you're getting too close and unable to see all the PFD/MFD's you'd like. For that you need to change the FOV as Oisín says.
White and orange balls needs to align for correct seating position.
Too far back in the seat.
Hi.
The idea behind the Challenger not having a maintenance system is to simulate or immerse you into being the pilot of the plane. As a corporate pilot you don't do much maintenance in the same way as you do if your an owner/operator of e.g. a TBM. The only similar maintenance feature you see is in the menu: Challenger 650 > Ground Services > Engine Oil replenishment system, as that's something the pilot of a CL650 would be able to do themselves.
FBO for the TBM is a maybe at this time. Others have also suggested it.
You need to hold the toe brakes, and set the parking brake while holding the toe brakes. If you simply apply the park brake, there will be no braking effect. You can still assign a button for it, but toe brakes needs to be held as well.
If you bind CL650/checklist/prev_checklist you can go back in the checklists and find Quick Turn Checklist. It doesn't have custom audio implemented yet, that's a known issue.