Hangar Flying

Is there anyone in this group who can say which current type of Styrofoam is acceptable to use in wing construction? The only variety I’ve seen mentioned on this site in past comments is Styrofoam FB but that variety is not listed on Dow Chemical’s current web page (construction materials) so I don’t think it is made anymore. Aircraft Spruce sells “Square Edge” which is listed on Dow’s site but there a few other varieties which are more robust (i.e. – compression strength, density, etc.) than “Square Edge” and they may be a better choice. I’m trying to avoid the high cost of shipping (it doubles the price) from Aircraft Spruce by finding the foam at a local supplier but I don’t want to invest hours of building in a product that is unsuitable. Any comments?

Thanks,
William