Bug,
I have thought about your problem, i.e. can I safely aerotow out of a particular strip with a particular tug. Here is what I came up with.
When I was getting a tow pilot checkout, we did some simulated tows with no glider on the back. We just used a lower RPM, and took off & climbed with less power. If you roll the super cub up to 2200 RPM with no glider, it may perform very much like it does running full out with a bird on the string. If you do an aerotow with the glider, observe your ground roll, height above the obstacle at the end of the field, and climb rate out of ground effect. Then pick some RPM that feels about right and see if you can duplicate the performance that you had towing, with no glider. Once you have a good RPM, fly over to your proposed field, short yourself out of 200' (or whatever is appropriate for your rope length) and give it a go. Of course, if you don't have enough margin, you pour the coal to it and climb out with full power. A bit safer than just trying it for real.
-- IFMU
PS on the "The Private Pilot Flying Album" thread I posted some soaring pictures. If you haven't found them already, look here:
http://www.pprune.org/forums/showpos...&postcount=423
and here:
http://www.pprune.org/forums/showpos...&postcount=410
and here:
http://www.pprune.org/forums/showpos...&postcount=412
if you are interested...