First Ever Grow CFL La Diva Auto

Well to start off hello all and thank the rollitup community for all the help and information i have gotten. Now to the pretty stuff ^.^ This is going to be my first ever grow so i went with La Diva which is a Delicious seeds brand blueberry x Diavlo (a Auto flower) says should finish in 42 days so ill be able to see my first creation early.
Im using a PC case i made with:
two fans (one blowing in the other out)
3x 26W CFL's 6500k for Veg
3x 26W CFL's 3000k for Flower
PC case dimensions are 15 inch long,7 Inches wide, 11 inches tall ( 38 cm long, 18cm wide and 28 cm tall
Here is where im most worried about this whole grow i only have 11 inches from the floor of my PC case to the CFL bulbs so im expecting once i put in my Pot with my seedling i will haven even less than 11 inches so with anyone with experience will this be possible? Also debating to go with 24/0 or 20/4

Im unsure as to what soil im going to use, something from Home Depot most likely in canada. was going to get Miracle grow but everyone is warning to stay away so im a little unsure as to what to use. Going to mix 30% perlite and maybe 10-20% Sheep or cow Manure.

im using Miracle grows nutriends 12-4-8 for Veg and then some Cactus feed for Flower which is 2-7-7 hopefully there is nothing wrong with these two.

Well i just put one seed aside to try to germinate it and get this show on the road as i dont have space for multiple seedlings ATM.

I do have some questions though about LST training on a Autoflower that only takes 42 days im not sure when i can start it to prevent my girl from growing tall.

So if anyone has any info about my case height problem or when i can start LSTing and fimming my autoflower girl that would be very appreciated. Cheers (sry for any errors its 6:30 AM and im high and tired as shit )

Alright so update time, today my baby girl finally sprouted a root, so i put her into a tiny plastic cup with soil and perlite and tossed her into my grow box. A couple concerns though if you guys could help me out. I put a crappy dollar store Thermometer in the box and im getting 30-32 C im worried its too hot. i have an Exhaust and Intake and i also have an extra pc fan around. it would be a pain but i might be able to add it inside the grow box maybe? Will i have to or will she be fine.

Second concern i bought a PH water test and ive used it on 2 day old tap water and got a reading of about 7.3 and then i went and tested a water bottle and got 7.2 so is this really bad or could this PH test just be off (prolly not likely). On that note i hear the most common problem with new growers is over and under watering. a guide or timeline when to water would be great.

As always thank you guys so much for you help stay high