Going thru this now with a friend
Rossi usa sales a base to replace the rear site, $14.50 + shipping
He needs to find a "shorter" scope but we put an Eotec "red dot" scope on for this weekend to get him by..... deer hunting !
Get the base mount and then scope like any other with the exception of the proper scope lenght but I would think any red dot type should work for you
hope this helps
Dave