Anyone any advice on something new to try im flowe...

There's no magic bullet. Keeping an optimal amount of nutrients around the roots is the goal. There should be plenty of each and in a ratio that doesn't interfere with each other. This isn't foie gras. You can't force-feed a plant. Are there more effective ratios? Sure. Is there much evidence for this specific species to confidently know which is the best ratio? Not so much. Will you be able to resolve such things growing 1-10 plants in your home? Probably not. So, keep'em healthy and happy. If you want to try a new ratio of nutrients provided, go ahead and see how it works on numerous grows so you aren't confusing genetic diversity with cause/effect of your nutrient adjustments. Maybe, in a couple years, if the difference is large enough, yo might notice positives or negatives. I'd suggest looking at the ratios that result from Jacks 321, masterblend, cropsalt, megacrop et al... they are all similar and based on the same knowledge base. I was lucky to run into it by my 2nd grow. I am completely confused by the perception that these are "picky" plants or are hard to grow. They are incredibly easy to grow competently. The esoteric formulas out there are why people think it's difficult to keep a marijuana weed generally healthy... if you meet needs and provide max DLI for your local variables, that's at least 90% of yield as far as what you can control... The underlying gentics are the ceiling. none of these expensive products are going to allow you to circumvent the 50-70g/sq ft ceiling for ambient co2. Some genetic freaks may do it, but nothing you directly cause.