LR2s can turn out real nice provided you look after them and they get enough light.
I use a mix of biobizz grow and topmaxx bloom and molasses for nutes, in organic compost mixed with perlite.
They grow to around 16", or atleast all of mine have.
Pot size neednt really be much bigger than 3Ltr.
Dont know what lighting you using but if youre doing CFLs, use an even mix of Daylight and Warm white bulbs or the first 3wks, then after they show sex, usually around day 17 for males and 21 for females, change to all warm white, maybe with one daylight thrown in to even out the light to a more natural spectrum.
Nutes can be given as soon as the cotyldon leaves fall off or shrivel up, i start a regime of diluted biobizz grow nutes at end of 2nd wk...
A few days after they show sex, back the grow nutes off to around 1/8th recommended dosage,and start adding small amounts of bloom booster and molasses...gradually building it upto around 1/2 recommended dose...Cut out Nute for the last 10 days, you can still give a light feed of molasses and theyll be happy enough.
Lowryders dont like a lot of nutes as a rule...
so take it easy with your nutes if youre new at this,as you can still give a good feed with the molasses..I use 1.5 tsp of molasses to a litre of mineral water.
No need to change light schedule, theyll grow real well with 18/6 as soon as they poke outta the soil..
Mine all look like this...
I got around 7-10 days flowering left on these..
Pic attached is a good indication of my average yield with these too, theyre great for continuous harvest setups..