I have an SKS Chainboard installed on my Xtracycle with a 3x8 drivetrain.
I managed to luck out, hard, in that I had no installation issues.
I think that it may be due to the fact that I ordered the one for a 48t chainring, and mine is only 42. Also I have a Deore dual pull front derailleur, that mounts lower on the frame than the stock Alivio did. I didn't have to cut out the part of the Chainboard that is designed to be removed for derailleur clearance.

The crankarm and chainwheel clearance is very, very tight. I have got just enough clearance so that the crankarm doesn't hit the Chainboard.

I installed the Chainboard for drive train protection from the elements, as opposed to preventing chain tattoos.
I also made a cover from a flexible cutting board, for the non drive side, that is duct taped to the chainboard.
Now about 80% of the chain ring(s) is/are protected from crud thrown up from the front wheel.