7 speed freewheels

[RecordAceFromNew]

Thank you for your advice. However, he didn't say that Alvio wouldn't handle 8 or 9 speeds, only that higher spec Shim derailleurs wouldn't handle 7 speeds.The question is, really, are the above-Alvio models all in fact 10 speed changers?

This is rubbish. All current Shimano 5/6/7/8/9 speed rear mechs have consistent cable pull characteristic. In fact even their 10 speed road rear mechs have the same cable pull characteristic, only their 10 speed mtb rear mechs have different cable pull characteristic.