Strength, Elasticity, and Extensibility

I'm a bit confused about the meaning of these terms - my doughs have got too much or too little of something, but I'm not sure what.

I'm trying to make whole wheat bread with 66 - 75% whole wheat and 75 - 85% hydration.  I make a poolish using 1/3 of the total dough weight, 100% hydration for the poolish, and a little bit of yeast calibrated for an 8, 12, or 16 hr fermentation of the poolish.  When the poolish looks good (little bubbles, frothy), I add the remaining flours (whole wheat + high gluten) and water, incorporate, and autolyse for 30 minutes.

Then I add the yeast and salt, mix (sometimes in the KitchenAid, sometimes by hand), stretch and fold at 30 and 60 minutes of bulk fermentation, then sometimes overnight bulk fermentation in the fridge, sometimes right to preshaping.

Preshape and shape, and then into the basket for 2 hrs.  I can usually preshape/shape a boule with some surface tension.  For batards, the dough seems much stickier than the videos, it does not stretch like the videos, and the seam just gets lost.  

Then mist, score, and  bake on a hot stone in an oven with steam. 

• The lame gets caught in the dough unless I am channeling Mac the Knife
• 75% hydration boule mostly holds its shape after transfering from the basket to the peel; 85% hydration spreads a lot
• If I try to use the dough for pizza crust, it tears when I try to roll it out or stretch it.  It does not stretch the way the doughs do in the SFBI high hydration shaping video or in others
• There is a little oven spring, not much

Photos of one of the better results, still not so good:  https://photos.app.goo.gl/JwiVUyoaajRpwgX99

Too much elasticity, not enough extensibility?  Or vice versa?  Inadequately developed dough?  Overmixed/undermixed?  Overfermented/underfermented?  Overproofed/underproofed?  

Thanks.