well i plan on doing that. but i dont want it to completely drain while im painting them and the MC dry out

 

The mc wont dry out. If you're planning on painting your calipers it should only take a few hours from start to finish. Its relatively straight forward and will be easier on you if you complete remove them, clean them up, paint them, then re-install. Once finished, bleed the brakes starting from passenger rear then working your way from furthest caliper to the mc.

What color are you going with? I'm not a fan of painting calipers but to its own.

 

As crazy as this may sound golf tees tend to work well. They're tapered and made of hardwood so
They won't break. Put one in the line and one in your caliper.