As long as you have enough room from the edge of the cabinet to the edge of the sink it shouldn't technically be a problem.

That said, having the sinks not on center in the cabinet would drive me absolutely up a wall and I think it would look like a mistake. I would also not do a single 3" filler but rather two smaller fillers so that the vanity is centered on the space. Things that I expect to see centered and that look like they are close but not quite always looks like poor planning or craftsmanship to me.

thanks for the feedback. sinks 15" from the ends seems tight to me but he alternative of going to 33" wide sink cabinets and shrinking drawers to 15", only moves the sinks a couple more inches and kills my drawer space. Maybe I'm making this too complicated. Any suggestions on cabinet configuration to fill 83-84"?

I agree on spreading the filler. My problem is one side is against the tiled tub which is 2' high. Not sure how I put a filler between cabinet and tub. I could get bigger cabinets and avoid the filler altogether, but then I'm taking a risk that the cabinets fit in the space.

Maybe I just need to bite the bullet and hire a designer. I hate to spend the money when I just need help configuring an 84" vanity but I'd also hate to do something stupid and ruin the entire project. thanks