If you don't mind advice from another novice... I've built and flown control line models for over 40 years and dabbled here and there in RC but just got back into RC and successfully soloed our trainer last year.

Yes, the LA 40 will fly NexSTAR trainer. It won't be a rocket ship though...

I built the Sig Kadet LT-40 as our (my son was 13 when we built it) trainer but it is both lighter and has a larger wing than the NexSTAR so it will fly slower before stalling. My research said the LT-40 kit tended to build a little on the tailheavy side. With a much larger wing than the NexSTAR (900 sq. in vs. 722 sq. in.) the LT 40 is going to have a bit more drag than the NexSTAR. The instruction booklet which came with the the Kadet showed an OS FP 40 plain bearing engine but I chose a Thunder Tiger 46 Pro ball bearing engine.

A couple of reasons for doing so: First, since I fly control line I have a lot of FP 40s and equivalent laying around. I didn't want another FP 40. Second, I chose a heavier engine to help the LT-40 balance without having to add any lead weight. I despise having to add dead weight to ANY airplane. Third, to counter the increased drag of the LT-40 I went with a slightly more powerful engine. It *has* helped when trying to punch through windier conditions. It also bailed me out when I inadvertently got into a bad situation fairly close to the ground once. My TT 46 has a lower pitch 11-5 prop since I wanted THRUST, not top end speed.

I think air bleed carbs are just as reliable and easy to set up as dual needle carbs. They just have opposite effects. Close an air bleed screw and you richen up the idle mixture. Close the low speed needle and you lean out the idle.

The OS 46 AX is probably the better choice *if* it doesn't require you to add additional tailweight to compensate. Otherwise, go with the LA 40 or better yet, the LA 46.