.85
I do not know how much experience lies under your 'ATPL(A)'? Perhaps if you took the time to read the rest of the threads on this you would realise there is more to operating an aircraft than flying an ILS down to 200' AAL or less with which you seem pre-occupied. With an ILS DH of 200' I would suggest your walk-round would be more hazardous than any temperature error correction. Think of Non-precision apps, some with high DAs, and - of course - enroute MSAs which can be in error by over 2000' in extreme cases. The actual errors at a DH of 200' are lost in other altimeter errors, and of course the rad alt can NOT be used for minima unless so specified, can it?