It makes sense, giff, but where do you stop drilling holes? If you bought it kiln dried it'll be close to where you need it anyway. It's one of the more stable woods, but you're right to be cautious.

Google for info on moisture content (there's squillions of words on it out there), some of it appearing to conflict. It all depends on the type of meter and it's application, the section of the timber...

R. Bruce Hoadley's definitive 'Understanding Wood' has sections on moisture running to pages. It's not as straighforward as some make out. The yanks relate drying time to the controlled humidity of their workshops and some of the formulas are mind-boggling. This link gives you an idea of how involved they get, though thankfully without all the formulae…

http://www.dewalt.com/Blogs/post/2008/10/Lumber-Cutting--Drying-(-5b).aspx

Much depends on where the thing you're making is going to end up. Dry it out too far and put it back into a humid or moisture-laden environment and you've got problems; don't allow it to dry out enough and put it into a fluctuating temperature and you'll also have fun.

I usually leave my k/d sawn hardwood for a couple of weeks, but my wood store is in the roof of a barn and has a good crossflow of air, and then cut to sawn dimension (cutting ALL faces to relieve surface stresses) and leave for another week (which will show up any movement) before final planing to size.

And for a general overview of Iroko's qualities...

http://www.tdveneers.co.uk/iroko.htm