I use the bottle method, but I have a vac pump on the exit hose
That way I do not have to touch the pedal and if the bleeder does suck any air, it goes to the bottle , not back in the caliper...and , of course , clear line.. not just for air monitoring, but for fluid color change of the new fluid..
There is no fluid in the bottle , as it is not needed with this type system....
The bottle is an air/drop trap that does not let the fluid get to the vac pump.