I've been mocking up a custom aluminum crankcase spacer which is 3 3/8" high weighing 3.14 lbs after drilling out 3 holes at 5/8" diameter evenly spaced in the back to reduce weight.

The spacer is bolted to an 8.9" diameter 10 rib flat aluminum pulley used to drive a Vortech V1 supercharger.
I found a Vortech crankshaft spacer weighing in at 5 lbs but remained concerned about the amount of weight bolted on to the front of the crankshaft.

I have an option to drill 6 more holes evenly spaced in the back of the spacer which should reduce the weight to 2.6 lbs. I attached a (poorly cutout orange circle) to see how the spacing looks. I drill these 2 3/4" deep leaving 5/8" thickness on the top for the over sized pulley.

I'm looking for opinions from those who have added spacers to the crankshaft to advise if I should reduce another 1/2 lbs or go as is at 3.1 lbs?