In terms of calculating the optimum enclosure volume, resonance, and bandwidth, is the Pi-align whitepaper the best source? I only ask since it is dated 1979, wondering if it is state-of-art for Pi-alignment.

Also, in the formulas on page 5, I don't recognize some of the parameters from the typical T/S params.

Anyway, any advice would be appreciated.

You can also use the sealed box method or the added mass method to find these values. Measurements of the electro-mechanical properties of a speaker are much more likely to be reasonably accurate than measurements that involve the acoustic domain, because finding electro-mechanical parameters doesn't require any acoustic measurements. So these kinds of measurements can be obtained with probably something like 20% tolerance using equipment that is commonly available to DIY builders.

Wayne