Air Filter Size?

I have a single 34 Mikuni on my 850.
The air filter is maybe an inch thick and about six inches in diameter.
Considering how big the stock air filter is, am I being starved for air with this setup?
I am at 6000 feet altitude, and run sea level slide and jetting. Plugs look fine.
Bike runs fine, just weaker than would be at lower altitude, would a larger air filter be of benefit?

A thicker model would be better in this case. If for nothing more than the positive effect of getting the back plate of the filter backed away from the entrance of the air horn. Borrowing one might tell the tale.

Always fit the biggest filter you can get in the space