Size of sump for 90 G ?

[Regal]

Hi guys, new to the forum.

I have just recently picked up a 90 G aquarium and I am turning it into a reef aquarium. I would like to do a sump for this, preferably a standard aquarium, here comes the trouble, the tank has no overflows so I will be drilling the tank myself and using bulkeads. The pump I am using is a dart pump and it is rated for 3500 gph I am dilluting the flow to roughly 2650 gph.

The real questions are, what size of bulkheads should I use for drainage from the tank to the sump, should I use two? Would a 29 gallon sump be sufficent enough for this? I am concerned that teh pump will drain the sump to quick before the bulkheads can fill it, I want the sump at a consistent level.

Thanks and happy holidays,

David