Silver in gliding requires a 5 hr flight, 1000m height gain and a 50km xc flight (not necessarily all in the same flight).
Gliding clubs tend to want tug pilots to have gliding time and plenty of flying experience for a number of reasons:
1. You will have some idea what is happening at the other end of the rope. Most glider pilots I know have no power experience, so at least one of you should have some idea what's going on.
2. The glider pilot is paying the club for the tow (and your flying), and thus would like the service to help them. I was once towed by a pilot who clearly had no gliding experience and an underpowered aircraft, and we ended up miles from the field at 500 ft. If anything had gone wrong (and turning left just as I'd been hurled off to the right by a thermal nearly helped this happen) would have put me in a field and ruined my day. Similarly, taking me miles down wind and dropping me in the nice clear blue, rather than under those nasty bumpy clouds, won't make me a happy bunny.
3. Tugging is potentially quite dangerous for the tug pilot. I'm constantly aware that inattention on my part could kill him or her (the biggest danger is me accidentally getting high in the early part of the launch, which can pull the tug's tail up and stall it into the ground). Gliding clubs don't like killing tug pilots or losing tug aircraft, so plenty of experience is seen as a good thing.
4. On the other hand, the tug pilot also needs balls of steel or the female equivalent. Student pilots get given "out of position exercises", and the tug pilot needs to know when to hang on and give the student (or even sometimes the experienced pilot) a chance to recover the situation, and when it's time to cut the losses and release the tow.
5. Many tugs are tail draggers - don't know whether this is because they tow better (Robins make good tugs) or whether the hard-bitten types who tow prefer a "real" aircraft.
6. Because of all this, insurers tend to place quite high experience requirements on tug pilots.
If this gives the impression that I have great admiration for the mad men and women who give me launches, that's what I intended. They all seem to enjoy their flying, but I don't think it's an easy place for the inexperienced.