I would like to add radiant heat to a room we just finished with rift and quartered red oak. It sounds like I would be having "Joist Trak" installed. There are two layers of 1/2 plywood subfloor. I am hoping it will be effective. Any suggestions or thoughts?

Radiant heat is a different type of heat compared to forced air and is generally less expensive to get comfort. The floor will eventually heat up even with a thick sub-floor. Put as thick of an insulation that you can under the heating equipment so there will be less heat loss. The floor is going to get warm for your comfort over several hours, or even days, so don't expect to change temperature settings during the day and at night and expect a short response. It will probably take as much time to cool down as it takes to warm up. I find that it can be uncomfortable sleeping in a room with radiant heat since I get too hot and opening a window at night don't make sense. Quarter-sawn wood will shrink after a while, but one half as much as plain sawn wood. It is the best choice for a wood floor. You can even have area rugs without any trouble.
Your engineer will let you know about the characteristics of your system.