Also- my countertop is noble grey and it has some obvious veining so Im concerned it wont be an exact match with the seam.

yeah, that's a great reason to have the seam at the sink -- they just need to fudge an inch or so at the front, which isnt so hard, and you avoid the whole question of getting a reasonable match in a larger area where changes in movement might be very noticeable.

it's almost completely standard where I live to do them at the sink. I've heard people here warn against that, but honestly, I just don't see it, as long as your cabinets are installed well and the counter is properly shimmed and secured. it should be just fine.