PJ1 or No toil filter oil works like a champ. K&N does too, but I have a ton of No Toil onhand for my dirt bike.
For R/C apps... put the new filter in a ziplock bag and coat the inside of the bag with the oil. squeeze the bag around the filter until it is uniformly lightly saturated. turn the bag upside down and let the filter fall onto a paper towel. Let dry for 10-15 mins, as the alcohol needs to evaporate. Install.
Also, try 3M Coban wrap for a prefilter. It sticks only to itself, filters well, and is completely breathable. It i designed to be used in wound care, but works spectacularly as a prefilter. Simply wrap it around your current setup (as a 3-stage) or take off your current outer filter and use this instead. A roll costs 3-4 bucks at walgreens, and you can easily replace the prefilter every heat.