Your plant looks pretty good and should eventually adjust to the soil as it grows larger. I usually use
Promix, which gives you pretty much total control over what you are feeding and supplementing, but some growers prefer the pre-loaded mixes. Different strains react differently to the different mediums, so results can vary unless you grow only one strain. The leaf clawing is pretty minor and not a good indicator of nutrient issues yet, but when the clawing shows up, it is much more severe than what you are seeing currently. Just keep it going and I wouldn't feed it anything for a month or so... sometimes the nutrients are time released and flushing won't remove any excesses.