Just started flower, How should I transition with nutes?

First time grower here. I've been using only Jack's Classic All Purpose 20-20-20 through veg, I'm now 1 week into flower cycle. Wondering how exactly I should start the transition with nutes.

I've done alot of reading on it, there are just so many different opinions I'm still a little lost. Well anyways I have 3 ferts to chose from or combine.

Jack's Classic-All Purpose 20-20-20
Jack's Classic-Blossom Booster 10-30-20
Grotek-Monster Bloom 0-50-30

At my local grow shop they highly recomended using the monster bloom in conjunction with a regular fertelizer program. I've done pretty well with not burning my plants yet. and would like some advice on how to go about this, also with using the Jack's Blossom Booster I've heard that I should eventually double the recommended dosage, so 1/2 teaspoon per gallon. Is this correct?

During flower you want to reduce your n to somewhere between 2 and 4, increase your p & k to 50-30. I would suggest you drop the 20-20-20 altogether and only do 1/2 strength of 10-30-20 and the lowest recommended dosage of the 0-50-30 for use with other nutrients. (Usually this would be a 1/4 tsp per gallon)

Good luck. What strains do you have running?

Thank you for the advice Melvan,
So just to clarify (I do smoke alot of weed, bare with me)... The Jack's Blossom Booster says to add 1/4 tsp of nutes per gallon of water, since I'll be watering with nutriated water everytime. And the monster bloom says add 1 tsp per gallon of water.

So I should cut the Blossom Booster down to 1/8 tsp and add the full tsp of the Monster Bloom per gallon?

Not sure exactly of the strains, one may be a mango kush. They were all from bag seeds from some great medical grade stuff out of Cali. Had 7 plants at one point but 4 were male. Let them veg for months, since I had that few girls. Started with cfls for about 2 months, Vegged for a month with my 1000 mh. My grow journals kind of lacking lol. Have pics of them up with the dates they were taken. Flower under 1000 hps now,

They're gonna be some big girls come harvest time. Here are pics from today

Seeds out of medical grade smoke? I see hermies in your future. Keep a close look out for those nanners. If it is truly medical grade and there were just few seeds it's a good possibility that the weed came from a hermied plant.

You may be alright, you never know what's going to happen when you grow a hermied seed, but they could be prone to do the same. It could also be it was just a mistake the grower made leaving a male they thought were female. Still, keep a close eye out.

They're looking nice and bushy, good job limiting your stretch.

Thanks, they went through some stress, this just being my first grow. But I'm happy with them so far.

As far as I know it was all medical grade, had an almost direct connection, but unfortunately not being in a friendly state can't really be a 100% sure about it. But yeah I'll keep my eye out for that.
Will being starting with some fresh feminized seeds next time.