You don't need the Nitrozyme - it's a nitrogen heavy product that is good for people who take loads of cuts from mums because it helps generate new cuts. More for the bigtime commercial guys than percy imo.
Boost is a flowering booster....some people say it's snakeoil....but it's probably a cocktail of all kinds of stuff. Canna claim it makes the plants photosynthesise more/faster/better, and so in conjunction with more PK as the fuel, it rocks. I started growing using the Canna UK calculator and it is a blinding way to start. They don't tell you to overfeed your plants and it forms a great basis for your own tailored regime (with or without Canna products).
I've literally just stopped using Boost because of the B'Cuzz boosters but it'll be interesting to see how my plants fare on the new stuff. Will do a side by side shortly.