Dick,

have you ever heard of the set of exercises called "Hanon" - they were originally for keyboard (Piano) - I had a beginner book years ago, but were also done for Piano Accordion sometime in the 1930s - I've also got a copy of that somewhere. Try
http://www.google.com.au/search?hl=en&q=hanon+accordion&btnG=Search&meta= for some links to find what I mean.

Originally done by Charles-Louis Hanon (1819-1900) see - http://www.piano-pal.com/hanon.htm and
http://en.wikipedia.org/wiki/Charles-Louis_Hanon

Hanons were also done for other instruments too - don't think one was done for the Concertina, but if you got hold of one of the originals, you could 'translate' it ...

I mention this because 'The Hanon' is an ordered systematic set of exercises, to practice both musical techniques such as you are mentioning, as well as physical exercises for the fingers - with concentration on strengthening ALL the fingers, and teaching them to be comfortable working independently of each other - some pedants criticise this idea.

Just thought you may find the idea useful.

Robin