What size Carbs for 471 stroker FE

[A98Coupe]

I'm currently having my 427 S/O motor rebuilt to give more torque & power in the useable rpm region for Street and mild competition. My motor was a fairly stock 427, LeMan crank & rods, 0.524inch cam with 245 duration @ 0.050 lift. It has iron medium riser heads topped off with a Blue Thunder 2x4 with 2 x 390CFM Holley carbs. CR was 9.8:1. It pulled 450hp @ 5,500rpm before strip down.
The changes I am making are as follows:
- RPM steel crank 4.125" stroke - should give 471 cu inch for +30thou bore.
- SCAT H-Beam 6.700" rods
- Diamond pistons - flat top or slightly dished to give 10.5 ~ 11.0:1 CR
- Comp Cams 294S cam, 0.605inch lift and 248 duration @ 0.050

The big question is how big should I go on the carbs without affecting throttle response & driveability? I was very surprised how much power the 'tame' 427 spec. achieved with 2 x 390s, so I am thinking that 2 x 450CFM Holley 4160s should give good results and maybe 2 x 600CFMs will give more WOT torque / power but poor throttle response?
Any advice would be appreciated before buying the carbs.