I used your ceiling in my rec room last year it turned out great. I reordered for my kitchen, also in the basement. Both rooms are next to each other. I put a wood boarder completely around outside perimeter and hung my angle  channel to it. I left three inches exposed and painted black. I used 2x2 black tile around outside and finished with geometric tile  in white inside. It turned out great. Best ceiling tile to work with ever. Thanks.