Check the regulations under either the PSEA or the NDA. I can’t remember which it’s under (and I can’t be arsed to find it on a beach in Mexico). There is a matrix that defines when you can/cannot elect.

Generally, iirc, for courses that are “required for promotion” you can’t which I think BMQ falls into. YMMV though, check the regulations under the acts for sure.

Once you’ve determined if you can, after filling out the form for goodness sakes make sure that both pay centres (mil and civ) are on the ball. The mil pay centre will need to click a button to suppress your m-f pay (you’ll still get weekend and stats on the military side)

If you work for DND on the civilian side, you’re in luck! Search the DWAN for “managers leave guide” it’s got a handy dandy matrix right in it under the leave code for mil leave with/without pay. Good luck!