I like the check board with the green at the top (your 2nd pic). To me that will be perfect. Definitely no sashing. I think the asymmetry serves the modern, fresh look you've got going here. The only other thing you might try with the blocks you have is a random-looking layout. Trust me, it takes a lot of effort to get that random look right. To me, your color scheme is unexpected, sophisticated, unusual in the best way. Like a surprise. And it really WORKS. Great job, keep going.