I always wanted some way to filter the air, but like you, i couldn't find anything decent. A buddy made the straight stack for me. The filter slides right over it. It is not a real tight fit but it is snug. I still may put a rubber band around it and secure it to the choke shaft. It only weighs a couple of oz's and is of the paper design. I paid $6.95 canadian for it.(about $4.00us) VERY cheap insurance.

I agree with you on the rear carb design. It is the only way to go. I've had the cowl off of my cap after a couple of weeks of flying and there is all sorts of junk lying around in there. I just didn't want to have my engine digest any more than necessary.
ttyl