Elite Volano with regular bike speed sensor

I currently use a dumb wheel-on fluid trainer, which I’m quite happy with, but recently I have been contemplating ‘upgrading’ to an Elite Volano wheel-off dumb trainer, which are quite plentiful on the used market here.
I know the Elite Mitsuru dongle will provide speed readings, but many are for sale without it. My question is, how practical would it be to McGyver my current standard Garmin spoke speed magnet sensor to work on the trainer? Is it possible, or an I just wasting my time?!