I'd go with Jack's Hydro along with the Calcium nitrate. They offer a package price for both.
I was using Jacks along with the cal nitrate and epsom salt in the 3-2-1 formula that somewhat popular. Recently, I was given a more optimal formulation which I really like.
2.5 grams Jacks Hydro
2.5 grams Cal nitrate
.25 grams potassium silicate
.25 grams ammonium sulfate (first 3 weeks bloom)
.25 grams ammonium phosphate (weeks 4 through 6 or 7 or 8 depending on the strain)
All weights are per gallon of water.
Big thanks to dizzlekush for this formula. My plants are loving it. I run on bulk rockwool with hydroton in 4x4 beds. I can't imagine why it wouldn't be ideal with a chow mix of coco and hydroton once the coco is conditioned.
I've never used the MOST so I can't really give any useful information. I know Capulator has experience with that item.
As far as the Bloom Booster, I've used it a couple of different ways. I've added it at a .5 gram a gallon to my base nutrient during flower and honestly didn't see any difference overall.
Its my understanding according to the folks at J.R. Peters that the bloom booster is a one time, stand alone shot. No need to add the cal nitrate. I've used it this way, as a single shot right around the 17 to 21 day mark. I ran it at 3 grams a gallon solo. It's definitely more effective used in this manner. Although I'm not going to say it increased my yields. It did make them stretch quite a bit more. Even at 3 weeks when they're usually starting to top out. All my plants looked great, no burnt leaf tips. At more than 3 grams a gallon I noticed I would get tip burns.
Since I've begun using dizzlekush's formula I don't see any need for the Bloom Booster. Switching from the ammonium sulphate to the ammonium phosphate at week 3 will give you the extra P that would otherwise come from the bloom booster.
This is strictly based on my experience using Jack's. I'm sure there are others who are more knowledgeable and can go into greater detail, especially regarding coco.
I hope this is of some use.