Filters arent really a complex thing.

Measure the space available to you, look at the shapes/sizes in the filter catalogue and order one that fits in the space.

https://www.knfilters.com/dimsearch/index/

 

Good that you pointed out the airfilter setup. I've done the math and found out that I should get a bigger one.

 

I will be testing pressure drop. I have a differential pressure gauge that seemed to work great to optimize ducting, so should work.

This is the setup:

Tube going into breather fitting, about 1 inch horizontal distance from the compressor inlet:


Tube Right at the air filter:


Both tubes are the same length and run along the same path to the cabin.

Does this look decent?
Is the filter tube positioned correctly?