Idle through high speed cruise will all be on the idle jets/progression holes. the problem is with the transition from progression holes to the main circuit. the bigger the choke, the lower the air speed and the later the main circuit starts.
There's richer and leaner emulsion tubes, yes, but thats not the only way they can differ. On the Dellortos, a .9 emulsion tube is richer than .7, but starts the main jet later. something to do with a hole at the float level lifting the emulsion earlier than without.
if you find an emulsion tube that starts earlier, and maybe it is richer, you can make it leaner again with smaller jets, but it'll still start earlier.