In my LAK17a, I use Coloplast Conveen Optima condom catheters connected to tubing (via two one way valves) and a 4 liter collection bag behind my seat.. I keep the bag in a waterproof outer bag "just in case)" You need to empty and rinse the bag every flight (obviously).

There are long and short versions of the condom catheters. I find the shorts hold just fine and are much easier to remove.

I'm pretty happy with that set up. It is a bit more convenient to have the tube run outside your glider via an external hole (as it did in my PW-5) but you do end up with a dirty glider and getting urine corrosion on any parts it hits / gets sucked up into.

Lou