separate keys for navigating between places in snippets, and for autocompleting within a place

EG, I am going through the snippet

for(int ${2:i}=0; $2<${1:count}; ${3:++$2}){

${0:/* code */}
}

My cursor starts at ${1:count}, and I want to type itemChainAngles.size(). Naturally I type itan<tab> to autocomplete to 'itemChainAngles', but of course this leaves the count variable as 'itan'
and moves me to the next place, ${2:i}. It would be good if it were possible to assign a different key to moving between places in a snippet than the one we use for autocompletion. I don't see any keybindings for moving between places, so it looks like, if its possible at all, I would have to rebind autocompletion to something less opportune than <tab>. You can see how this would not be ideal.