Steve/Date: 19 Jul 12 - 03:53 PM
"Having the keys closer together and minimum finger contact allows for much greater speed of course.(and also more buttons, more keys) For playing chords and slower numbers yes big buttons would be useful as on accordeons/melodeons".

The trad transversal c-c distance between buttons with the English is 12,6mm, with Anglo/Duet 16mm, and full size typewriter/computer ca 18,3mm.Professional "playing" when typing is at least as fast as with any concertina.The c-c distance for the English is so small that for all adults there is jamming between fingers which obstructs speed. The typewriter standard above is more anatomically adequate which promotes maximal speed.
Up to a reasonable practical limit I see no major disadvantages from a) increasing the measures of the English keyboard at least making it analogous to Anglo/Duet
b) incresing button diameter for all models to at least 7mm. For 30k Anglos 9-10mm is fully practicable.