Wisher69 did a fine job of answering the questions and really drove the point home in speaking about reading your plants and not measuring run off. Chasing runoff numbers is unnecessary IMO unless something MAJOR is happening but most of the time it's not accurate in the least.
I have mixed
vegbloom into ro water without issue and I have also tried mixing it into .2EC starting water(I just added tap water) Same solubility. No issues there. One thing I noticed in my solo cups over a longer period of time is if I used just ro without the .2EC worth of tap water my cocos pH would slowly drop, but after mixing in a bit of tap water to .2EC that problem stopped. I believe the .2EC of tap helped to stabilize my pH. Once again I only noticed these signs over a longer period of time.
I still water 1x a day with fresh transplants. This gets oxygen down in the medium consistently and helps promote faster root growth IMO. No matter how often you saturate coco it still holds a very respectable amount of air within.
I don't check my runoff numbers at all. Like wish said I just look at my plants and adjust accordingly. If I see burn tips or leaf curl I back off. If I see some yellowing I increase the strength. So far I have found that the sweet spot for me is actually what you just stated. About 1.0-1.1EC at a pH of 5.9-6.0.
I use em. I find I need to be pretty conservative with the PK booster(shine) though. +life is pretty strong and affordable in my opinion. The base nutrient could be slightly cheaper but it works well for me and it's not incredibly expensive. Just more so than
maxibloom which IMO is what most base nutrients should be compared to since it works so well.
The maxi series is really good. It's also cheaper than V+B and works wonders!