I think there is enough depth also, because I am tranplanting rooted clones...
therefore, in my experience/judgement I will be OK. IF they get top-heavy*...
...(Well, that wouldn't suck, or be the 1st time)...see above reply to Knowmy*

As far as perlite...I use it to mix with my soil or soilless potted plants...
I have always used hydroton, and I LOVE hydroton...perfect for most hydro...
I knew these trays would take every bit of hydroton, I had already...As I mentioned at top...I saw trays...light bulbs!!!...I was looking at a giant $35.
bag of hydroton and there was a giant FOXFARM Large perlite for $25...

I have read a few pieces on cloning in perlite, and these particles are much bigger than other perlite I have encountered, not to mention, all the Commercial/Hydro Tomato Grower's that I know...Use the beige hydro buckets filled with perlite, very successfully. So I thought I would try it...Thanks for response and Q's...lw