many of the hands you are 3-betting are callable. Like 67s or 85s. I guess it's ok to mix in some of them from time to time. You can probably widen your value range too to include 88, and you can add some off-suit bluffs like 76o

This is approximation. I just am curious for example how we should build 3bet range to guy who is opening on button 70% and folding to 3bet 70% and for example guy who is opening 55% and folding 60% to 3bet. Should we wide our range vs guys who folds more? How should we pick bluff/value ratio vs different fold to 3bets>

I'd like to pose my thoughts.

[Optimum calling 3bet range is approximately 20-33% according to 'Leakbuster']

If a player is opening the button 70% then an estimation of his range is:
22+, A2s+, K2s+, Q2s+, J2s+, T2s+, 93s+, 84s+, 74s+, 63s+, 53s+, 43s, A2o+, K2o+, Q3o+, J5o+, T6o+, 96o+, 86o+, 76o. 930 hand combinations. 

If he folds to 3bets 70% he would be left with approximately:
(1-0.7)*930 = 279 combinations 
=66+, A2s+, K8s+, Q9s+, J9s+, T8s+, 98s, 87s, ATo+, KTo+, QTo+, JTo.

If a player is opening the button 55% then an estimation of his range is: 
22+, A2s+, K2s+, Q2s+, J3s+, T4s+, 95s+, 85s+, 75s+, 65s, 54s, 43s, 32s, A2o+, K5o+, Q6o+, J7o+, T8o+, 97o+, 87o. 738 hand combinations. 

If he folds to 3bets 60% he would be left with approximately:
(1-0.6)*738= 295 combinations. 
This would look very similar to the previous estimated range with speculated extra hands such as suited kings, suited two-gapped connectors, unsuited aces. 

Comments:
-Regardless of the disparity in the opening ranges, due to their folding % the tighter opener actually has a wider calling range. 
-This calling range vs an estimated 3bet of 5-8.5% isn't profitable!



To actually answer your question is requiring hitting the fundamentals of +ev blind play. I would recommend purchasing, calculating or reading some material to increase your knowledge on this spot, to create some ranges and then refine your question.