Brian,
No matter whether you use 8/4 or 16/4, you have a kick-ash bench
I made my top from 8/4 maple and selected flatsawn boards for the top, which created a quartersawn top when laminated. I build as a split top, which I high recommend. With the caveat that I didn't like the split top and later glued the halves together. It was only then that I needed help with the build. I built it with the BC tail vise, which I use all the time.
Good luck and hope to see your progress posted here. And it will be o.k. if it takes longer than you think--mine took almost three years to finish
Best,
Chris
"You can observe a lot just by watching."
--Yogi Berra