Routing joists for beam on pier deck

Hi All,

Building a large deck 46x16, and just realized my joist on beam is going to require a fair amount of planing effort as joist can't be made level as simply as when built with joist hangers.
Instead of building and then planing after, I was wondering if this makes sense:

1. Place all joists crown (top side) down on sawhorses, clamped together face to face.
Reason? In this setup, all the tops of the joists should be close to level.
The bottom of the joists which will bear on the beam are now off-level, and facing up.
2. Make a router sled
3. Route a 5" channel across the joists at the 2' and 14' length where my beams (3x 2x10) will be, just deep enough that all joists will set level on the beam when flipped over. I expect this to be no more than 1/4".

So now when I install my joists, the notched area will lie on the beam and the joist tops should be very close to level. I know this probably sounds like a waste of time, however if its feasible I'd rather do this beforehand than lots of planer action afterwards.

Appreciate any critiques.