So for example suppose I call the bb against the button and he cbets 50% on QT2r. I need to call 66% of my range in theory. Which hands, exactly are the 66% of my range? Sure I can go to equilab and it`s easy to see but I need to come up with that answer on real time. How do you guys study or manage that?

So my question is, which methods are good for studying range balancing and range construction so that I can apply that more effectively in real time during my sessions?

NOTE IM NOT ASKING HOW TO BALANCE OR CONSTRUCT A RANGE. I already understand the theoretical concepts behind all that(well, for the most part). I just want to know how to practice/study doing that in real-time

I think there's only one big answer: PRACTICE.

A lot. Everyday.

Putting ranges in Flopzilla (better than equilator), looking how they interact against each other, playing with the weights, calculating the top of the ranges, the low, seeing which cards are better or worse in the next street...

If you practice everyday, even if it's only 10 minutes a day, you will see results in a short period of time, improving your decisions in real-time.

There's no another answer, imo.

It generally a mistake to play MDF on flops,. MDF is all about making villain indifferent to bluffing but on flops your opponent is still going to have equity, unlike river spots where your bluff catchers may be good. As such you might find yourself over defending on boards where villain has a range advantage or underdefending when you have a range advantage. Board texture matters far more than MDF on flops. You are going to have a lot of bricks out of the BB where you simply aren't going to be able to realize your equity over multiple streets. Flatting out of the BB you most likely are going to have around 400 combos of various holdings, and having to defending 240 combos in this spot will likely end up costing you money in the long run. That's why playing out of position is so bad. Your opponents bluffs are still going to have equity. MDF is much better utilized for river spots.

That being said, what I do is I first work my way top down with all my best value hands. So on this board I would assume you have around ~4-6 set combos (QQ and sometimes TT 3bets pre). 9 two pair combos, no overpairs, AQ at some frequency, KQ, QJ, Q9, Q8 Q7s Q6s for around... ~60? top pair combos. Then count your Tx's (36-50ish?)... and maybe a couple of hands like 77-99.

Then figure out which unmade hands you are either checkraising or check calling with, so hands like j9, KJ, AJ, most other gutshots etc. Then maybe some backdoor combo draws like A3hh, a4hh, a5hh etc

If you do this and think about this often you'll quickly be able to approximate the number of combos you should be continuing with