Can anybody comfirm that a Mustang daytripper will fit with ridgid mount side plates,small luggage rack and low or medium backrest? Thanks in advance.

Dunno about the luggage rack but it fits with ridgids and a low on mine. The only problem is the bolts on the side plates touch the outside edge of the seat. It may cause wearing in the seat over time. Easily solved with some rubber caps I would imagine.