I assume that solo instances are not intended at all unless on the off chance that you somehow are the only person queueing(unlikely right now).

Something else no one seems to have mentioned is that it's possible for the instances to be full, hence while during peak hours in the evening you can have a 5 minute+ queue to even get into the starting lobby. So realistically, right now if you're in a solo instance during peak hours then you're potentially making 23 other people wait.

I'm mostly asking because a lot people are attempting to figure out how to rig their way into a solo instance consistently so they can farm the achievements.