Seems that I am probably tricking myself too much into my postflop skills as I insta-flat both.
However, I used to always 3bS QTs and most frequently flat QTo before I started flatting both.

One point that people don't really seem to mention. If you are jamming hands like QTs/QTo your flatting range is going to become a lot weaker and even though jamming may well be max ev for these hands I'm not sure it's max ev for the combination of flatting + jamming ranges. Unfortunately very hard to quantify but I do think that jamming sometimes and flatting sometimes will maximise the ev of your strategy. Also becomes a lot more difficult to play against when people do see you both flatting and jamming hands like this pre since they are then they have to try and guess what hands you are jamming and with what frequency you are putting hands in your flatting range and in your jamming range. Also I think one thing people do poorly is they see you flat QTs and jam QTs, so they know it can be in either range. Then when they do a post flop calculation in game/later they don't weight ranges to take into account that a hand like T8o is more likely than QTs, which leads to some incorrect assumptions and the best way to capitalise on this is to mix in flatting/jamming.

It's possible I place too much emphasis on trying to strengthen my bb flatting range based on weak emperical evidence and hurt the ev of my strategy because of it. I have never actually done any thorough calculations on this (and doing so would most likely be fruitless anyway without looking really deeply at my entire game which would take way too much time) but intuition and logical thought does make me think that this is more likely to be right than a 'I prefer flatting' or 'I prefer jamming' approach.

Nah I agree that we "should" be flatting some prime shoving hands which gets sick value to balance a wide flatting range oop.

But I still say to jam QTs before QTo. I.e. I mean exactly that if we were to jam QTo in some spot, we should definitely jam QTs, but not the other way round.

That's a valid point, and I'm hyper concerned about my range balancing as well (probably because I play a lot more cash games nowadays).

If anything, QTo makes up 12 combos while QTs only 4, so if you jam QTs and flat QTo I don't think you have to worry too much about weakening your flatting range.

And as for constructing ranges, it is totally possible that the best solution suggests we do 2 different things with the same hand, with some frequencies. For example, if we are to jam and flat QTs 50:50, we might as well jam QcTc and QhTh and flat QsTs and QdTd, etc. However, this usually leads to complicated strategy, and while it's true that opponents are more likely to make mistakes against this "mixed" strat, we too have to be careful and precise with the strat as well, otherwise we will start making mistakes ourselves.

And yeah, playing our hand (i.e. in a vacuum) and playing our range are two different things, often resulting in lots of confusion and different strategies :P

Given the wide difference between EV of QTs and QTo I doubt that both are at the indifference point and such to be distribuated both over a flatting and 3bS range.

I am not even that sure that one of these hands is at the indifference point when we focus upon max EV with total strategy.

I am also living by the idea that there is exact one combo at the indifference point. Although I can live with the idea that combo's of the same hand perform the same.
It would also not surprise me that someone could provide some evidence that postflop has the potential to generate situations that suddenly several combo's of different hands arrive at the indifference point and are split with certain frequencies over flatting & 3bS ranges.