With respect to cooling your SCT, you might like to read this & change tack..
https://www.iceinspace.com.au/forum/...sct+insulation
I now own the 7" Intes featured by Mental4Astro complete with corflute insulation/dewshield... works like a charm
Others who have gone down the path of insulation rather than cooling have had similarly good results...
It's a rather inexpensive option to try