Germination quesion: after they crack how much root tip until planting?

Only have four seeds total(3 strain-2,1,1) so I have to be perfect here.

They all popped a couple days ago and I checked them this morning and three seeds look the same- no root lengthening. I was thinking I need to wait until the tips lengthen to around a quarter inch but I also don't want to leave them in the wet paper towel medium too long either- fear of rot. One seed was perfect so it is in the planter. The three I have left just aren't "busting" out.

So my question is how much root tip before I drop them in the planting mix? I would just like to see them with a hearty root tip so I know they are trying to move forward.

I have carefully removed excess moisture so they are still moist but not soaked.

from when u see the root coming out a nice little bit i just drop it in the soil give them a water in the top (walla) within a week

I didn't wait for a root, planted after seeds cracked. All of them turned into nice plants. I think it doesn't matter, because there is a little difference for seeds between moist paper towel and moist growing mix. In addition, the roots will start growing in the right direction from the beginning.

onces you see the tip put the seeds in 1in x 1in starter medium and put under a humnidity dome and mist when needed. once you see roots (1-2 weeks) then transplant and start the nute program for veg. depending on the strain, veg 2-6 weeks them dump your nutes and start the flowering.