PVWatts thermal model intial INOCT value

Hi,
I took a look at PVWatts v5, and in there it says that the initial assumed INOCT temperatures for Fuentes model are:

49°C degrees for close roof mount
45°C for open rack and tracking

I was wondering if you could recommend an INOCT value for mounting configurations with insulated back?
I assume it should be a couple of degrees higher than close roof, but how much?

I understand this question may be difficult to answer, but I would be grateful on an assumption too.

Thank you.

Thank you Paul.
Great sources, both of them.

Do you mind if I ask how does PVWatts Fuentes modified model distinguish between different Module types (Standard, Premium, Thin film)?
I took a look at the original Fuentes paper and code you linked above and it only gives an opportunity to distinguish between different mount types by changing the initial INOCT temperature.
But how does PVWatts address the Module type in Fuentes model?

Thank you for the reply.

Thank you Paul.

In both penultimate and your last reply, the link attached for Funetes model is the one from 1987, released by Sandia:
prod.sandia.gov/techlib/access-control.cgi/1985/850330.pdf
prod.sandia.gov/techlib/access-control.cgi/1985/850330.pdf

So we are ok.

I checked both the upper 1987 Sandia publication and the fortran code in the Appendixs, and there is no mention of temperature coefficient involved in Fuentes model calculation.

Does that mean that PVWatts does not address the issue of Module type in its modified Fuentes thermal model?