Maybe it's just my risk aversion sense kicking in, but I wouldn't want to be using my Ethos 17 in a Barlow, it's big enough and scary enough as it is
Btw the 17mm Ethos is a 2" only.
From a practical sense, it remains to be seen how convenient it is to fumble around with the rings in the dark. Give it a go and report back
But most people go with multiple eyepieces....just sayin