I doubt he’ll accomplish it in Elbaf. Feels too early for a straw hat to do so.
This ties back into his introduction stating he has a "giant" army of 80 million men.
Zou gave us the concept of Sanji being worth 1000 men, and Zoro being worth 2000 (or so he claims).
So, if one powerful Giant is worth, say, 10,000 men, that takes us down to 8,000 Giants (8,000 x 10,000 = 80,000,000).
8,000 still might be too much, maybe more like 800.
Point being, if Usopp can gain command over a Giant battalion, he would be a Brave Warrior of the Sea, IMO.