Not sure about TR7 alloys but the TR8 alloys have a greenish tinge to them which is noticeable if you put them next to the Spiders wheels which generic paint name of argent (which is silver in French.) With that in mind I have just painted mine as they were getting a little long in the tooth after 37 years. I used Duplicolor High Performance Silver wheel and caliper paint followed by their clear coat paint for wheel and caliper. It is about the same colour but metallic in bright sunlight but not in subdued/indirect sunlight. You're not going to find the original colour for TR8 wheels, I'm sure, so any silver/argent color will work. Eyes are not created equal and see colours differently (discounting the various types of colour blindness) witness those pictures in various colours where you see numbers or animals in a mono coloured picture and many can't see anything whereas some can. Personally I've never had any problem seeing what's in the picture but that doesn't mean I see colours the same as you if you can as well.
- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT