Seeds-n-sun
I have good luck with the Miracle-Gro premium potting mix, which I add perlite, vermiculite & cow manure to. Very lite mix that drains quickly but doesn't dry out too fast. Not sure about ur lighting, perhaps some1 with better knowledge of what u have can help.
As far as the seeds go, every1 is different. I started some Blue Dynamite seeds in April & 4 sprouted on May 1st. All were transplanted into 1 gallon containers after the 2nd set of leaves developed. 3 are solo & 1 has 2 plants in it. Plant #1 went crazy right from the start. Plant #2 also shot up quickly & its partner grew next to it @ a slower pace. #3 was slower developing & #4 continues to grow the slowest of them all. #1 showed signs of overheating after transplant & I cut off the leaves that were curling up & moved it outdoors to recuperate. New growth still has that annoying upcurl but otherwise the plant is healthy. #2 is in 12/12, the larger of the 2 is female, putting out a few white hairs @ the apex of the plant after 2 weeks Its cohort appears to be female also. Give it a day or 2 & I will know 4 sure. #3 topped itself & branched into 2 stalks very early. Not as large as #1, but has caught up to #2 in size. Definitely female & showed 1st about 3 days ago. #4 is the runt, but is a beautiful plant, healthy, happy @ half the size of any of the others, about 25cm. Leaf development is behind the others as well. Still I have it in 12/12, which may be early for it, but I will continue until it is sexed, then put it back into veg state. #1 is on its own in the great outdoors, while #2 & #3 will be flowered out. Keep in mind these are 7 weeks old. If you show the Rhinos love & care I think you will see them make a leap of growth very soon. I start 1/2 strength nutes with most seeds @ 3 weeks & they tend to respond with rapid growth. I also spray the leaves with 1/4 strength nutes every few days @ the same time. I use 18/6 lighting.
Right now I have 3 additional sprouts that I culled from a bud of high grade commercial out of California, that I'm fairly certain is a Mexican type that produces enormous buds. 2 came up in a few days & 1 in a week. They are 2 & 2 & 1/2 weeks sprouted, respectively. 1st 2 got leggy, while the 3rd is showing signs of being very squat. I have had them all outside for a week & the legginess has vanished like magic. All are very healthy & loving the big halide in the sky.
So to answer the 2nd question, my slant on it is put em in the sun & watch em grow like mad! Today is the longest day of the year & its hotter than hades most places, so why not take advantage? Just remember to keep em watered, as they tend to dry out quickly in these weather conditions outdoors.