Yes I understand whilst you see things on the net you have no idea if they broke after 1 mile or 1000 milesThe guides are intended for a derailleur but have their own bearing unlike any other derailleur I've ever pulled apart. Maybe the better derailleurs have them?
I'll admit I hadn't considered the swap from return to drive side of the chain with the resultant extra forces. I have seen these incorporated into other people's builds on the drive side but that doesn't mean they didn't make a mistake too.
The rule of thumb [ if there is such a thing ] is that the diameter of the drive side pulley should be greater the greater the angle the chain goes through [ the forces are greater and that means the drag is greater ]
So FWD twisting chain bikes may have a pulley of 4-5" diameter.like this :-
Your chain change angle is less so you should get away a smaller pully , but IMHO those derailleur jockey wheels were never intended for those forces.
Have you found this thread ?
Converint stick bikes to FWD
Might help ?