[help plz] grow setup + strain info. how much yield for a 3 month grow with sog?

Hi! this is the first time im growing, i have been reading alot about growing cannabis and the real effects of this awsome plant for over a year now.
I would like to know how much grams i would get.
I'm thinking about ordering the strain from "SensiSeeds.com".

Strain info: (Marijuana Seeds White Skunk Cannabis Seeds Review)
->Name: White Skunk
->Type: indica-sativa mix (65% indica - 35% sativa)
->Climate: indoor/outdoor
->Yield: 450 gr/m²
->Height: 50 cm
->Flowering period: 9 weeks
->Harvest: begining of september
->THC level: 20%

Grow setup info:(ordering from "kaya.es")
->Light: HPS, 400W = 53.000 lumens
->Reflective plastic: 15 square meters of Mylar
->Area: 1 square meter
->Grow Medium: Soil
->Fertilizers: None, except the soil has n-p-k levels above 10 to 30, i dont really rember the exact values
->co2: no
->fans: i might put one during flowering stage or after 2-3 weeks of vegetative stage
->fresh air: yes

Growing stages:
From seed to begin of flowering stage: 3 weeks to 1 month
Flowering stage: about 2 months

Number of plants 5-10

I would like to know:
->how many plants should i grow?
->how much yield should i expect?
->should i order this strain from another bank?

I need to grow a strain with a thc level above 18% to make "rick simpson's hemp oil" to cure cancer.
I will stick with the soil that i have choosen and i will not use co2 because of the cost and i have no idea where to get it.
I will have to do it in no more than 3 months and 2 weeks.
I will not use a lamp with that spends more than 400w.

BTW im not the one with cancer but someone in my familly instead.