Today's little gem for free: once you grow from seed you'll always have too many plants
Never to many, not anymore, lol.
:::::::The rest of this are my finding and do not represent the "best way" to do it, or the "correct" way to do it:::::::::
So here are how the kids turned out. These are the same 7 cacti from the previous pics. What were suppose to be Hakuun Myrios turned out to be a mixed bag. One is Columnare, another seems to have Capricorne in it. And a few Nudum Vars. The E.Multicostatus really reacted great to the outside ligth.
One thing learned, DO NOT use any top dressing the is of a particle size less then 2-3mm. So take your <1/16" turface etc. and put it in a flower bed, imo. It is going to do nothing but turn into a layer of concrete and try to choke out your kids.
On the fertilizer side if things I can not speak for what you are using. For me I had to cut way down on the concentration in order to avoid literally plugging my turface with deposits. And that was at a 1/8 cut. So I wil be going for around a 1/16 mix or less and mixing in straight water.
Will post another thread on my year end result pics. Got 229 cacti out of 480 seed. Just finished re-potting today and moved outside. Bad light though, will take pics in the morning.
I hope this was of some use to someone.