As to changing the coolant ....

My workaround is ... I only remove the drain plugs in the heads when I
need to make the system DRY.

I do, however, flush and change coolant once per year as it tends to
lose it's corrosion inhibitors.

After draining as much as I can by removing the hose to the lower part
of the radiator and opening the expansion tank, I remove a big hose in
the engine compartment and plug a homemade adapter into it to which I
attach a garden hose.  I run water through it 'til it's clear (flushing
the radiator at the same time).  I then reattach the hoses and run the
engine for a few minutes .... flush again.  Then drain as much as
possible.  Where it doesn't drain there is only clean water.

Then I button up ... pour in the new antifreeze and top up with water
... bleed ... you know the rest.

Mike
'84 GL "Mongo"
'85 Westy