I cannot decide on what to do. 4 SA-15"s in a standard ported wall, or 4 SA-15"s in a 4th order bandpass.

What are the positives and negatives of both?

I've helped build a 4 15"s wall in the 60's and an 8 12"s 4th in 60's.

I like them both, both sound good, both played well. I just cannot decide on what type of enclosure to build.

C or B pillar wall?

Quarter wave wall ??? What tuning you thinking, about 57 htz ???

What did you end uo doing with your front stage ???

B-Pillar wall. I'm a man lol.

Front stage is still the same.

Very nice Drew. Should be loud as hell whenever you figure it out. Not to get off topic but can I ask what the purpose of your build is? SPL only with a high tune or a lower tune that you can meter/demo? What kind of power are we talking about here? Good luck bro! I'll be tuned in.