How To Value Single Mnh Stamps Of British Colonies - Specimen?

I have several dozen SPECIMEN stamps from the British colonies. Mostly MNH and a few MH. My Stanley Gibbons catalog only lists prices for complete sets. Thanks in advance for any suggestions on this topic.

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Looking at sold listings on ebay might produce some results. Likewise on stampauctionnetwork

There have been threads here which opine that you should apply the approximate ratio that a given stamp's value has in relation to the set's value. I don't subscribe to that. (I might have thought that in the past; might have even shared that thought here.)

Specimen sets were created as full sets. Generally speaking, I believe there are about as many 1d as 5/ specimens. A full series of regular postage stamps was not generally printed in equal numbers. There may be many times more 1d stamps printed than the 5/. Specialist catalogues may share the printing numbers of the various denominations.

An expensive high-value single might be more available as a specimen. Collectors might think that the specimen is a cheaper way to get the underlying stamp. That may artificially inflate the value of the high-value specimen? I suppose you could argue that it isn't artificial?

Anyway, take from that what you will. My opinion.

Thank you very much for the information