Hi Dan, welcome to the forum, thanks for joining us.
I'm probably not the right person to ask, as I ended up just ordering a pre-cut "kit" from Watershed (meranti) but with the price of Okoume being about 1.65 X that of meranti, I'd just stay with meranti unless extreme lightness is your desired outcome. While not having weighed my boat, everyone who has ever lifted it or helped flip it is in agreement that it is well under 500 pounds, and with keel/bulb coming in at 175 pounds, foam/CF rudder & the carbon rig/sails and hardware will bring the total to well under the 800 pound class minimum, I'm sure.
So my point is it's easy to get a really light build and spare the extra cost of okoume in my opinion. This being a forum, I'm sure there will be other opinions!

btw, nice cradle and I envy you your building space!
Tim Ford
hull # 87
http://nbayracing.com/i550Build.htm