I'd take the 7rds of most effective ammo. If you're more effective with a .45, then take that. I'll take the 10mm, thank you very much.
In our state, we are limited to 10rd magazines for deer hunting, to make it more sporting for the deer. We are limited to 3 rd. plugs/magazines for shotgun hunting migratory birds, to make it more sporting for the birds. We are only allowed to have 3 fishing poles in the water at once, to make it more sporting for the fish. And in some designated trout waters, only single point hooks are allowed (no treble hooks or multiple hooks) to make it more sporting for the trout. In NYS, they only allow you to have 7 rds in your defensive weapon, to make it more sporting for the killers and the rapists. Sad, very sad.
On the up side (I'm an eternal optimist), this new law is going to go a long way towards improving marksmanship. You can no longer waste the first 10 rounds of your mag in a panicked spray and pray. Every shot has to count now, because 7 may or may not be enough to get the job done. Aim carefully! And get the heck out of NYS as soon as you can.
A handgun is only good for fighting your way to a rifle.