If you look at an A10 frame from above,the top tube splays out to become a Y shape towards the seat. An A65 frame top tube stops earlier to form a T shape. An A65 tank will probably need its tunnel widening at the back to fit the frame.
IMHO opinion a large capacity A65 tank isnt as pretty as an A10 one, the A10 one has a flattish top, whilst the A65 is more rounded on the top and looks more bulbous.
A standard A10 tank has to be a better bet...
I take it you saw my recent post?
Cheers,
Iain