Before I forget, to prevent the sleeve from kinking/folding where the cap's edge and the coronal ridge is, use a TheraBand or something similar to create a gap filler, provide additional seal, and increase traction for your glans even further. This reduces the stress load on the sleeve and stop it from ripping apart under stress. In due time, the sleeve will wear out. Keep the old stretched out sleeve and put it over the new one, essentially doubling the layer to hold onto the cup and the base of the glans. The double layers will slow down stretching even further by as much as 80%. Too much experimentation on my end at this point.
Also, make sure to keep an eye out on the upper portion of the cap. Moisture will build up over time, and the maintenance is required for the cap. See here: