If your "slope" is going to be something more modest such as a dike or line of tightly growing trees that you may happen to find then a lightly built 60'ish inch DGL (Discus Launched Glider) would be something that is quite appropriate. But keep in mind that the lift zone from modest features like these is quite limited. It will hold up a 1.5 to 2 meter model just fine but it won't lift it up to much more than twice the height of the feature that is creating the lift. The smaller lift ridges of this sort don't affect the airflow over a big enough area to do more than create just a little hiccup of this sort that doesn't extend very far from the feature. So while they will hold up the glider they won't generate the big lift zone needed to get enough altitude to do any aerobatics.

I've soared off lift from a tight tree line on occasion and if there isn't a guy with a stopwatch breathing down your neck counting down to the "max time" for a contest task it actually gets pretty boring, pretty quickly. It's fun at first to know you can do such things but it's more of a "survival" trick for getting your flight time.

As a result I'd suggest you think about it in this light and figure out if you want to optimize the thermal aspects moreso over the small feature slope soaring aspects. And this mostly means size. A 2 meter or larger thermal glider will do far better at thermaling in all aspects than a small one. And if it should come down to needing that "survival lift" off a dike or tree line it can still use the lift as well as a small model. The ONLY advantage of the smaller model would be for slope flying on a much larger hill or cliff where you want quicker handling. My own feelings are that for general sport soaring a 2 meter to 100 inch model is a great size. It's big enough to stay in good view while ranging out farther to look for lift. But they also break down well for transport and storage. Smaller models get small too fast and you will find that you just can't search anywhere near as big a block of air for lift. Now if you're confined to fairly small parks then perhaps a "vest pocket" soaring solution IS a good idea. But only if this will be how you'll fly it all the time. A smaller model can be made to a lighter weight and turn far tighter. And that can help a lot of you're dealing with a lot of smaller thermals and other small spotty lift in tighter fields. For example a park with a couple of soccer fields or 2 baseball fields in one area would be perfect for a 50 to 60 inch model. You could certainly fly the bigger ones there as well but the smaller size would let you work some of the smaller lift pockets more effectively.

Getting back to the ailerons again. If you've flown and are very comfortable with polyhedral designs and can handle the perspective issues of flying out at a far distance then ailerons can really help you to sharpen up your glider handling. But if you don't have a huge amount of flying time with poly ships then go real easy on the aileron size and throw. They should be set up so that they are about as responsive as a power trainer model and no more than that. Otherwise even small control inputs will get you into big trouble when you're way downwind in a thermal and are flying the model as much on habit as you are on visual.