Either version works. A 90 deg filter is easier. I couldn't find one locally so I used and straight filter and looped the fuel line around the hose between the air box and carb. Having had issues with water in fuel before, doing the filter like that also has the benefit of having the see-through filter as the lowest point so the water will collect and be visible there.
This shall pass, be still and know.
2006 XT225, UNI filter, ProTaper bars, MSR handguards, SS front brake line, Shinko 241's.