Is there an 'ideal' print environment temperature for the M200?

Been trying to figure out what is causing pillowing on one of my printers, and then the other day noticed a support structure that was finishing off was pillowing on my other one (or rather, the bridging was melting, resulting in holes). This particular support is always super difficult to remove so this is probably why (extra adhesion on raised 'pillowed' parts of support).

It occurred to me that this was after the heating had been on a lot in the house, and the room temperature must have been in the mid to high 20's, and probably 30+ inside the printer enclosure, all with side panels.

Now I know 30c isn't exactly a high temperature for an enclosure when printing in ABS, from reading it should be 50-60c+.

But with a 50-60c+ enclosure surely any cooling on the plastic is going to be a problem, especially if I am observing pillowing at much lower temperatures.

Possible solutions are dual fan shrouds, but would take a fair amount of experimenting.

Do any of you have enclosures for your printers and if so what temp do you keep them at... and have you had cooling problems?

I ask all this as I am building an enclosure for my printers soon, I'll have to keep a close eye on the cooling issue.

(both fans are working on both printers)

edit: I also need to experiment with lowering the extruder temp, as I'm using filament at the moment and the 275c temp of the M200 hot end is very much on the high side.