For synths that use CC-over-NRPN (like the Circuit Tracks), assembling NRPN messages is pretty simple in a script:
function sendNRPN(ch, MSB, LSB, val)
-- nrpn address msb
sendMIDI({ 176 + ch - 1, 99, MSB })
-- nrpn address lsb
sendMIDI({ 176 + ch - 1, 98, LSB })