The tabs were confusing me by causing me to miss some new emails that were incorrectly getting filtered to deals.
I turned off the tabs and only have the primary inbox.
I still have the lab for multiple inboxes enabled which shows all my stars under the main inbox.
I did not need the tabs since I already had a good label and filtering system in place.
As for composing, I figured out
how to open the Gmail compose window in the center of my screen, but once I knew I could do that I still only do it 50% of the time. I don't bother moving for quick emails.
The way I have my monitors arranged, and that it's a widescreen, having the compose window open in the bottom right by default is awkward, but I'll live.
The Gmail web interface is still my primary email interface, they'll have to try harder if they want me to leave