I think its important to think of a good solution, since we may want to retrofit some other chambers.

For the electronics to drive the heater, let's make sure not to use the power supply solution that is in use now in LIGO and at the 40m. We should make sure to make the design such that the residual temperature noise from the heater is below what we expect for coating thermal noise, assuming we use Fused Silica spacer of 1m length.

This should be quite easy in principle, especially with the radiative shields on the inside.