No disrespect to you but I am very curious as to why you say it is hard to to get OEM casio straps for this watch? I am in the USA also and it literally took 10 minutes to find and buy one. Ether look at Pac Parts. If they don't have it in stock, look on eBay. I was able to find a DW-5600E strap a few months ago for $17 when I needed one. It was brand new in OEM Casio packaging.
I use these folks for a lot of my strap needs
Casio Watch Band DW-5600 DW-5700 DW5750 G-5600 G-5700 GW-B5600 GW-M5600 GW-M5610.
www.ebay.com
All straps were brand new in sealed Casio packaging. They used to be my go to place for GW-5000 straps but the prices on those have risen quite a lot.
Speaking of GW-5000 straps, they are very comfortable and a lot of folks dump the straps on the GW-M5610 for these straps. (the DW-5600E and GW-M5610 straps are the same while the GW-5000 straps are more supple and longer)