Buttons and fabric with a grid pattern

I have just been able to cut and begin sewing on my dress for...yikes... this coming Sunday.  Once I got started, I had to ask myself,  "Why did I pick a fabric with a grid pattern?"  Mmmmmm...not sure this is going to work but we shall see.  You can do your best to line things up when your cutting out but some how things go wonky when your sewing with a soft weave fabric.  Okay, the next question is about what buttons to use.  I am making a grand effort to use material and notions I have on hand not go out and buy more.   With that said, I am looking at 4 different sets that I have of vintage buttons.  The dress has 4 buttons with two of those being functional. Do I want them small?  Large?  Do I want the color to contrast?  Blend in?  Here is what I have so far:

The ones to the far left I like because their texture goes well with the cloth I am using.  The off-white with dark blue decorations are cute but they are really small.  The blue with the grey centers are actually a faux leathery pattern with a metallic center.  I like those and I have them in two sizes so that I can place the smaller on the bib front of the top and the larger size on the bib front of the skirt.  The black with a silver center (bottom of the image) are nice - simple but black.  Any suggestions?

I had thought to pipe the dress in a contrasting color like red or white but time, time, time is not on my side.  Then I thought to top-stitch with a contrasting color but my top stitching isn't the best so I don't need bad stitching to show.  I think this is just going to be a plain, simple dress this time around.