If you transplant from mg to ff remember your girls most likely will go through a shock. also id start in a smaller pot next time to get a good root ball going. then when you transplant they really explode.
do not flush MG soil with time release fertiliser. every time you water it releases some of the nutrients. you will burn fuck out of your plants. just make sure you let the soil dry almost completely between waterings. should help with the nute burn and stop you releasing too many nutes in the soil.