I think you are looking at balistics tables, and thinking like a bolt gun user, even asking advice from bolt action users here on GB. This will get you into trouble, as they (bolt action users) don't have to pay near as much attention to the pressures they load to.
You just can't treat a break open action firearm, not even a Valmet 412, like a bolt action firearm, and there lies your problem. I suspect you are headed for "action" problems.
Here is the BEST Valmet 412 advice you will ever get! Buy the 30-06 and use it!
OK, i'm done now...
DM