As of right now, there is no way to control the cache size. Hopefully this is addressed soon in an update. It has rendered Gizmo, something I used to use daily, completely useless for me other than as a Theater View remote. The cache fills up my SD card and gobbles up so much bandwidth that I can no longer stream over 4G without using up my entire data plan in 4-days.
I do not know about #2.