Haven't ordered from them yet. But I've heard that they are good quality shirts. I'm based in Cebu also and also sourcing for a good quality shirts. Like you I also prefers ring spun cotton coz its light than what I have previously used and my international customers can save on shipping.
I think TayBee in Manalili have available Blue Corner shirts but I think its only round neck and few selected colors. But I'm not sure if its Blue corner or Blue Cotton.
You may try order couple of pieces from their webstore to see the quality.
If you order 20K minimum worth, I think they will ship it free.
There is also a dealer of these shirts in sulit.com
Maybe you should also check. Heres the link:
BLUE CORNER T-SHIRTS Philippines - 794639