Questions when starting rockwool seedlings?

One random day i just suddenly decided to give rockwool, particuarlly grodan, a try. I set all my promix, soil and aspirations aside and ordered up some grodan starter cubes 1.5" to be exact from Growell here in the Uk. I also wanted H2O2 or any similar hydrogen peroxide product as i wanted to keep things sterile.

Below is my last promix seedling, hopefully rockwool is easier!!!

Questions-
I soaked rockwool 24hours ph 5.5 (i did order Grodan and remember exspressly saying Grodan not Growthtechnology rockwool! Grrr Growell plus they had no H2O2 but i just picked up 6% solution from local pharmacy). Then ran fert solution at 0.6ec of Cannastart then planted.

Five days later up came a root! Wtf, read like crazy and redid everything but plant pointy side down not up (my mistake! wrong way round).

So five days later and here i am with first sprout breaking surface.

At first i covered the tiny seed hole but it locks it in quite firmly so dont know here, i had to free my seed from the rockwool as it pushed up as seemed stuck at points.

I seen some plant in wide holes that are much wider than the seed and some plant in small snug fitting holes. Whats the deal here as it seems hard for the root to initially penetrate the rockwool and hard for the sprout to push of its rockwool cover?

Also is 0.6ec cool for germination, seems obvious to add ferts at planting since propogator keeps them moist till they sprout?

I have other questions relating to watering feeding but would prefer to feed measured amounts to keep air water ratio good?

I kind of know its going to take a few attempts, the sprout has not seen light yet but it will after 24hours as want to take it slow make sure its rooted.
I am nervous that the root wont penetrate the wool, dosent seem to part easy like my promix. Also its a touch purple in places but i am considerate that its early days plus im a noob to hydro.

I havent used any H2O2 and my last purchase was Roots Excelurator from H&G although id just like to start with ferts and add stuff only if really needed. I plan to start using H2O2 from start to finish as this grow has no place for organics.

I have some fresh Grolux T5's for its first day of light (god there very purple and think ill mix them with some pro blues at 6500k soon.

Above is the first seedling to surface and after carefully coaxing the shell halfs out of the hole i can see the root firmly in the side of the rockwool hole. Hopfully succes here with it rooting and a couple of others planted two days after are pushing up to plus a group shot of those left in the propogator, root hairs visable too.

So far i love rockwool, so easy and clean plus very cool