I think with a tank that size or going to need something bigger. I just did a 140 gallon and the skimmer wouldn't fit in the 30l sump I had. If u can have one made or do it itself do it. Ull never regret it.
I did a 30 gallon sump for my 135 gallon tank. It works. I am happy.
But, if I did it again. I would go as big as possible.
Bigger gives more water volume, and more room for any upgrades in the future.
Bigger would allow easier placement of equipment.
Good Luck