I've never worked in perlite myself - really hate the stuff.
But couldn't you just stay really ahead of yourself and keep the clones in a solo cup/T5 "nursery" setup for a longer period of time. That way your clones are very much well rooted in the party cup and you've got enough root ball to keep everything pretty much together in a 16oz cylinder of perlite.
I like to do this anyways so that I've got a very nice well established hardened "clone" when going into my room, be it straight into a flower room with a bit more veg before the flip, or into a "dedicated" veg setup. I don't count these days as veg until it hits an actual big light.
Yes and this is exactly what I do. All the same some perlite still falls out, particularly from the top of the cup since this is what dries out fastest and few roots grow at the top. The plants can reach 12-18" tall in a 16oz cup. That's about .5m to the rest of the world.
If I had better success cloning in a different medium, I would use it... But perlite works and I'm not about to change.