You can use $POS as part of the wav file name, for example "position$POS.wav". You then just have the small task of recording position1.wav, position2.wav and so on.
Then, rather than a Queue Position action, use a generic action in the callflow that simply plays a series of entry prompts:
'queued.wav' - eg. "You are in position"
'position$POS.wav'