Carb spacer for 416

Hi everybody:
just get one of the new 850 Holley Ultra carbs no. HLY-0-80804RD for this combo:
dodge 360 060 over
4" crankshaft
Icon 744 flat pistons
Comp Cams 242/248@050, 549/544 lift
Ported Eddy heads
Rpm airgap port matched
150hp nitrous
904 with trans pak
3000 stall torque converter
9" rearend with 4.56 gears
28X9X15 drag radials
front skinnies
Caltracs
The car is a '74 Duster street trim
for street & strip usage
I have two spacers: one 1/2 inch open and one 1 inch 4 hole
Wich one is better to use?
Thanks