I just balanced last night and happened to snap a pic of a couple of "tank on" balancing tools.

The first is a pair of german-made slipjoint pliers from Sears.
For some reason, their shape and size makes them handy for all kinds of stuff.
The second is a Milwaukee brand angle driver on a socket & handle.
There are other brands out there too.
They're all priced around $20.
I have a question on this topic too.
What's the size/pitch of the balance screw?
Hex or socket head might be nice there.
It looks like M4-.7, but I thinks it's a finer thread.
I tried a screw that was M4-.7 (I think), & it went in about 3/4 turn & stopped.