i use vitalink max
http://www.vitalink.eu/en/_range/vitalink_max.htm
i have heard others say its not so good for being high N during the flowering stage
i have had not problems with it, my plants look nice and green
before this i used canna , i cant tell much difference to be honest
i think vitalink keeps them greener lol and its a little cheaper
the system i use (NFT) will accommodate large plants as it allows for a big root system should the plants be genetically inclined to produce one
on the same runs of all these larger plants below i had plants (sisters) that only yielded from 3 to 5 oz
the large size in my case is for the most part down to the genetics of these plants
some sativa genetics can have huge growth spurts during early flower
in the case of the 15.5 oz plant this grew from 7 inch to 4ft tall in the first 4 weeks of flower
during this stretch the plant grew many branches and bud sites
this one NLXBB yielded 8.5 oz in 12 weeks from seed
this below Biker kush is 2 plants trained into a big bush, the biggest plant yielded 18 oz the smaller 5 oz
these were clones they got a bit bigger than i intended they were old mother plants that i cut back many times
when i flowerd them they exploded with growth
this is the biggest plant i have pictures of it yielded 21.5 oz
it was vegged for 4 weeks being heavy on the haze side it flowered for 14 weeks
peace
yeah indoors is an entire different ball game compared to outdoors. The only draw back I ran into outdoors was thieves, and BUGS!! 
other then that everything was gravy.. 
Hopefully the K.A.S.I. will take on the weight from the cross.. Keep your fingers crossed with me.. haha..