Do you think the 276cfm is enough for that? I do this as a sideline in the evenings and weekends so I need something that works pretty good, but I dont have to have the best.
I've been running the black box for over 6 years now. Almost never turn on motors 3&4. I mean, like NEVER.
So - after all these years as a professional furniture/cabinet maker, I've not burned out a motor, had a piece slip/shift and now feel I could have saved some cash and simply built a box for 2.
Yep- once in a while, a really curly piece of ply lands on the table. Not even 4 motors can pull the worst ones 100% flat, but unless there are dados/rabbets on the offending corner, things still work out just fine. Based on your stated use, I'd vote 110% build a black box if you'd rather not burn the Becker bucks. Your choice to build for 4 motors - never know what materials you'll encounter in the future.

Get it done, and you'll be loving life. Vac hold down is the single most important accessory for your table. (next to a motor to spin router bits!)
Good luck!
Jeff