San Joaquin Sourdough - not quite..

Well, I thought it was time to try my hand at David's famous San Joaquin Sourdough (by the way, does anyone know where the name comes from?).. My attempt went reasonably well, but the results are lacking.. I fed my starter mid Saturday morning and placed it in my oven with the light on. Within four hours it was easily doubled and an active bubbly stew of yeast! It was literally bubbling as I added it to the water! I followed the recipe pretty well other than to ferment in the fridge for 16 rather than 21 hours - to better suit my schedule. 

After dividing, I shaped the dough into two boules and let them rest - they had very good surface tension. I then attempted the Hamelman batard shaping. The second batard was better than the first, but I couldn't really create tight surface tension. And by the time they were proofed they seemed more floppy than not when I went to transfer them onto some parchment paper.  The larger of the two in the picture below was a little stuck to my linen, so it's shape suffered a bit more too from the transfer.

I cut the smaller one tonight and found the dough towards the middle of it's length definitely more dense than the ends. And some of the holes throughout would make me think it was a bit over-proofed. Maybe my starter was 'too active'? Lastly, yes, i tried to slash, but again found the dough pretty slack when I did (again little surface tension) - and of course I'm not quite yet there at getting a good slash just yet. I'll definitely try this again. All advice welcome. Thanks..

this one shows the bottom part of the loaf much denser/moister in the middle of the batard..