This unit does have an integrated Picatinny/Weaver mounting system, so it will work on your picatinny rail.
This uses a CR2032 battery.
The American Tactical Imports Tactical Electro-Dot Sight will fit any firearm that uses a flattop picatinny rail.
The American Tactical Imports Tactical Electro-Dot Sight, Red/Green, Four Reticles can be mounted to a Benelli Vinci if it has a picatinny rail on the receiver.
The only options would be either that there is an issue with installation or there is an issue with the parts. If you are installing properly, then it is likely that either the rail you are using or the red dot are potentially out of spec.
Yes, these are pretty low.
You can co-witness AR height iron sights through this optic.
Per the manufacturer this optic has a 3 MOA dot.
Please reach out to the manufacturer for that information. 800-290-0065 customerservice@americantactical.us
This optic is designed to be used independently of iron sights.