If I can figure out how to make my digital camera work and get pics transferred to the computer (I'm not quite, but almost, a Ludite) I'll shoot some orc pics and let you see.
I like that Reaper article but for most minis I like do do the stripe method. 1)paint the white 2) paint a vertical color stripe for the iris (about a #1 brush with well pointed tip) 3) paint a narrower vertical black stripe for the pupil. Don't worry about the top and bottom on those stripes because 4) Take the same #1 brush and do horizontal or eyelid matching stripes in either flesh tone or hair color to cover any slop created in the previous steps. Works like a charm 95 out of 100 times!
If you look at real people on the street there are very few in which you see anything of their iris more than a band of color so this method replicates that quite well and all you have to do is make straight lines with your brush.