>> "deep" 606 inserts
I always wanted to try "deep" inserts, but when I tried mailorder, they were always out.
But I found a local wholsalke place for nursery/greenhouse supplies (Steuber's Distributing). They have some very deep (like 4 + inches) 50-cell propagation trays. They seem slightly sturdier than some other prop tyary, and of course much sturdier than tear-apart "insert" trays.
I think it was $3 for the tray. That makes each cell only 6 cents, but when you go to push each seedling out of the tray, it is less handy than single tubes. Being able to b uy them locally saves S&H, which can be as much as the cost of the trays.
Usually I cut prop trays up into 3-4 rows of cells when I want to turn them upside down to shake seedling root balls out. The 50-c ell trays divide into 3 sections: 15 cells or 20 cells. Since I sldom fill a whole tray with one variety, that works out OK for me.
(Cutting them down to just two rows is possible, but then they are tippy.)