I am replacing two bathroom vanity tops. Both vanities go wall to wall. One needs a 61.75 inch wide top. The other needs a 47.5 inch wide top. Both are single bowl. Don't want to replace the whole vanity, just the tops.

At Lowes, I can get a standard off the shelf 61 inch white cultured marble vanity top for $209.00 plus $35 for two side splashes. I can get a standard 49 inch top for $149.00 plus $35 for the side splashes. If I order the custom sizes, price quoted is approx. $525 (61.75") and $415 (47.5"). Installation cost separate for both options. If I was going to pay those custom prices, I can get granite for less than $100 more total including installation (not white, though, which is my preference; I already have the granite quote for giallo ornamental, same as will go in the kitchen).

So, I'm trying to decide if I can fit those standard sizes in the space I have. I will have to pay someone to do the work (I'm 51 YO woman, not able to fit under vanity to remove the old or install the new). Here is what I am thinking. Will this work?

1) 61.75" vanity top: center the vanity top and put filler wood strips on either side. They would be 1/2 inch or less, so side splash should cover them, right? I will be paining the cabinet, so no worry about trying to match a stain.

2) 47.5" vanity top: could we cut out the drywall somehow to fit the 49 inch top? What about trimming it off at each edge? Website says if you cut the edges of the top it voids the warranty. I read somewhere you could use a concrete blade on a circular saw to trim the edges.

Suggestions???

EDIT: this is not my exact condo (it's in the same complex), but you can see how the vanities go wall to wall in the pics:

http://www.realtor.com/realestateandhomes-detail/4206-Pinehurst-Cir_Little-River_SC_29566_M52157-40768#photo9