To answer your 1st question, this cannot be done just by calling a single command. Manually, you would change the order of the channels in the portal and then you would have to call the function that changes the channel numbers according to the new order. Programatically, you would hav to do more or less the same.
Its much easies to use Formulacalc to store the results in a specific channel:
ch(#):= ... Uses the next empty available channel for the result
ch(3):= ... Uses explicitely channel 3
ch("[1]/speed"):= Uses explicitely the channel with the name speed inside the first group. If there is no channel with that name, it will be allocated.
regards
Ingo Schumacher
Systems Engineering Manager CEERNational Instruments Germany