General Help Tuning?

[90Vette]

First, let me say I've done many hours of research, including searching for answers on this site, to try to figure out everything I can myself. I apologize if I ask a question that's already been answered, but I did my best to figure it out on my own (a big part of my problem is that I often find two conflicting answers).
That being said, I still feel like my grasp of tuning is incomplete, and I haven't been making much progress on getting my BLMs to 128.

My process is this: I upload the latest bin to my Ostrich 2.0 emulator, allow the car to enter closed loop, and then go for about a 25min drive to datalog. With my dad in the passenger seat reading TunerPro's BLM history table, I do my best to max out sample counts (I have my ADL histo set to max at 50) in as many cells as I can. Typically, that will look something like shown below.
History table.PNG

Then, using Trimalyzer (I used to use a homebrewed Excel spreadsheet but found Trimalyzer to work better) with the filters shown below, I modify my VE tables, and I inspect Trimalyzer's knock map, dropping a degree or two of timing in cells where knock is seen. Using Excel, I also note my average BLM and BLM standard deviation. I then upload this newest BIN to my ECM, and repeat the process.
Trimalyzer filters.PNG

The issue is, my BLMs don't seem to be getting any better - in fact, my last datalog showed I am pretty far off, when just a few BIN revisions ago I was pretty close (average of 127.2, standard deviation of 2). BIN history table is shown below, with the most recent at the bottom. What am I doing wrong?
BIN history.PNG

• Is smoothing VE tables necessary? Even my most successful tune's lower VE map looked pretty jagged (seen below). Part of me wants to get it nice and smooth, but the other part of me thinks the complex engine dynamics could well result in the actual VE of the engine varying in such a seemingly unsteady manner.
• How good is good enough, in terms of BLMs?
• Do I need to disable EGR? None of the guides I read mentioned this, but I just saw a post today saying it must be disabled.
• Does ambient air temperature have a major effect on BLMs?
• Is dialing in my spark table crucial to pass smog?
• On that note, is there anything specific I need to fiddle with to reduce emissions?
• Which tables do I need to mess with beside main spark advance and VE?
• Does $8D pull data from VE cells surrounding the one it's in like some other ECMs?
• Given that CA gas has 10% ethanol in gas, should I change target AFR to 14.13:1?

VE Map.PNG

My car:
1990 Corvette base model with ZF6 transmission
383 TPI, AFR heads, Lunati Voodoo 262/270
1227727 ECM, $8D mask

Thanks in advance.