that is my one regret: not being able to see the fluid level in the 1 1/2" cleanout (bent T). I look forward to your article... (I'll prolly be kicking myself for not thinking of it first
)
I found that the best way to bleed my system was pick up the top half and turn it all kinds of upside down, sideways and everywhich way... so after about an hour I had all the bubbles out...
Tokamac