Unless you have an ISCG mount they go on\in the bb.
I just use the lower roller. No suck and not too many $$.
Adapt the roller shaft to be longer and it would do a double?
Sorry, I run single. (38 to 11-30 is da BOMB!)
Guides can be noisy, but work.
No other info from me, I don't have the ISCG mount and am not even sure that's the right spelling.
Pretty sure.