Quick question: Need light at my stage?

I know its basic but ive been searching all morning and feel like i have mixed answers.... So my seeds have germinated and have little white tails.. my ph adjuster isnt here until mid day today but heres what im doing now..

Placing seed into water soaked rockwoll with the white tail pointed down and then putting it in my grow box to keep it warm (around 76degree) and cover it so no light gets in?

Pretty much when does it get light?
and
Do i need to adjust the ph for the rockwoll cube first or can i use bottled water and let it sit out for a little?

Is it ok to leave the germinated seeds in the paper towels that long??

So is one 42watt cfl ok to shine on the rockwoll or would you suggest it stay in the dark?

And last one... do i adjust the water to about 5.5ph and then put the cubes in and hope its ok after that? or check again?

As with all roots, keep the taproot away from light. Should be fine letting them sit in the paper towel, though. I've had seeds with one inch long 'tails' that I had to cut-out of the paper to plant. Had no problems with them at all, but that was really pushing it, I think. (I ran out of soil for a week)

I've never used rockwool, but isn't 5.5 ph water, combined with using the (acidic) rockwool, a bit too acidic to start seeds...? I have heard of others' rinsing and squeezing the cubes, to alleviate this, (like rinsing out a sponge, rinse, squeeze, rinse, squeeze...) but don't know firsthand.