Re: 1 - piece base or 2 - piece base for 10FP?
Most benchrest shooters use two-piece scope bases.
Aside from being able to deploy various devices on a fully-slotted Picatinny Spec Rail, which means maybe you need rails over the bolt cut-out area on your bolt-action rifle, there is nothing to gain from a one-piece base.
Have heard a lot of arguments for the one-piece base from "tactical shooters" over the years, but none that is applicable or verifiable unless you want to use a variety of devices or position your scope forward for prone shooting etc.
A one-piece base does NOT strengthen your action or add to its rigidity; unless you WELD it on.
A one-piece base can be just as out-of plane as any 2 pc base, UNLESS you know that your action is perfectly in accord with the blueprints the base-maker used.
You have a better opportunity to tune a 2 pc base setup with shims or other means to assist alignment than you do a one-piece.
When a benchrest shooter has to get groups under .1-.15 to place in the finals, do you think they would handicap themselves with gear that didn't work? NightForce and Leupold make 2pc Picatinny spec mounts. I have cut the bridge section out of a NightForce one-piece mount and gained an extra slot fore & aft.
I hope this is helpful information.