The newer 212 and 220 actions are a different diameter than the 110's so 110 mounts won't fit properly. You need a mount specifically for a 212.

Best option for mounting a scope on these slug guns is to use a full rail like this one from EGW. Using a rail allows you to place the rings as close together or as far apart as needed for any scope you want to use. It also gives you plenty of room to move the rings fore or aft to ensure proper eye relief with most any scope.

As for loads, most guys I've talked to seem to be getting good results from Remington's Premier AccuTip and the Hornady SST's.