ST 90 woulb be fine in the escape, but I agree with Lotus72d: the OS 1.20AX would be a great engine for the Rubin (originally designed for a YS 1.20AC). I have about 60 flights on a 1.20AX in a JR Explorer V90 whih is actually a bit bigger than the Rubin. I'm running an APC 15x10 - unlimiited vertical. Pretty good throttle response for a 2-stroke and sooooo easy to run - right out of the box!! Just 10% nitro, too. ST .90 or OS 91 FX would both be good choices for the Escape. I flew an OS 91FX with a performace Specialties Ultra-thrust muffler in a Widebody .60 with excellent results!
Good luck and happy flying,
Will B.