I went to Bunnings when I did mine - I took a HEAP of colour swatches and found one that matched the WH20 paint very closely and had them mix me up a sample pot for about $5.00
I bought a NICE quality small roller ( fine feel/finish - not a big lumpy texture on the padding ) and it came up nice.....here is a couple of my web pages that show the cabinet and backbox.


http://home.kooee.com.au/brainsnap/wh20.htm

http://home.kooee.com.au/brainsnap/wh20cabinet.htm