Mud flap questions

[musigenesis]

So I bought two replacement mud flaps to mount on my bus. One side is smooth and one side has a slight texture to it. Which side should be facing the wheel, the smooth side or the textured side? I would guess the smooth side to keep mud from sticking to it, but I dunno.

What should the clearance distance be between the flap and the wheel? I think it's 5" but I'm not sure. The replacement beam that I'm mounting the flaps to is (I think) an inch or two forward of where the original flaps were so I might have problems with them smacking the tires. If need be I can mount them farther back, but it would have to be on the undersides of my below-floor boxes so I'd have to trim them considerably.

Also, the bottoms of the flaps should be 6" above the ground?

[musigenesis]

Found this list of mud flap laws by state: https://www.minimania.com/pdfile/Mud_Flap_Laws_NETA.pdf.

Pennsylvania: All commercial vehicles or
combinations used on the highways must be
constructed or equipped with mudguards to bar
water or other substances from being thrown by
the rear wheels at tangents exceeding 22 ½° from
the road

And since I drive in Jersey sometimes:

New Jersey: Trucks, buses, full trailers or semitrailers of a registered gross vehicle weight more than 3 tons, must be equipped with metal
protectors or substantial flexible flaps behind the
rearmost wheel before operating on the highways.
If there is not fender, body or other protection
over the top of the wheel, some suitable protection
must be provided. The flaps or other devices
should substantially reduce the amount of dirt,
water or other materials thrown on windshields
of following vehicles. This rule applies to all
vehicles entering New Jersey as well as resident
vehicles.

Kinda vague. I think I'll just slap them up in the most convenient spot so I won't have to trim them at all.

[somewhereinusa]

Rough side towards the tire, it helps to reduce spray/mist. There are some that look like astro turf on the wheel side.

[banman]

I'd solicit someone with your model bus to measure where the mudflaps were.

Granted it's not rocket surgery but oem had a reason for where it was which is more often right than wrong...