First off, I'm a HVAC noob.

My 7800 btu "Home Brew" chiller tops out at about -25 thru -29c coolant temp, depending on if the two pumps (swiftech655/alphacool 24v) slow to a crawl sooner than later. The evap is submerged and sealed in a Rubbermaid cooler.

If I leave the chiller on for hours, it will get down to -42c without running the pumps/loop. In this case the temps eventually drop down to about -30c and gradually decline.

I get about 4c on a qx9650, vcore 1.70, @ 4928mhz.

I have the exposed line from the evap insulated.

I run a second a/c unit to get the room down to about 63f.

Questions:

1) Would I get better performance by throwing a heating pad onto the return lines from the evap?

2) Does keeping the room at 64f and subsequent cool air running over the condenser of the chiller hurt final temps or should I keep that as cool as possible?

3) Should I tear apart the 10k btu window unit that cools the room and use that instead? Or maybe pick up that cheap $200 dollar 15k 120v unit from City Mill?

4) Will an IWAKI pump fair better as a chiller pump? Suggestions?
Thank You gents!