Hi MBriggy
Your colour question about the KEVII stamp can be best answered by looking at the QV 1s stamp above it.
The QV stamp was issued in Green and Carmine according to Gibbons catalogue.
Given that, the KEVII 1s you show must be Scarlet.
In the UK, the 'rule of thumb' would be that Scarlet is more Red and that Carmine is less Red heading slightly towards maroon.
The cancels look OK to me. Not sure what the Scott remark is all about.
As to your assumption that you "will easily easily make the $25 I paid well worth it", it really depends on what else you purchased ofthe more modern stuff. The older stamp you show here would likely sell for about $10 so you can take it from there.
hope all my babbling helped a bit !

Londonbus1