Depending on the hardwoods he's using, they're likely heavier than forgewoods, though forgewoods were generally pretty heavy for their diameter. Forgewoods, being cedar, would also have different elasticity, springing back faster at the shot than hardwoods. To get the same flight out of the heavier hardwoods, you would probably need to go up in spine a little.
I have ramin wood shafts in 5/16 that are comparable in weight and spine to some forgewoods I have. Forgewoods shoot better IMO. I use the ramins for practice (they're very tough), but when it comes time to go after critters, I pul out the forgewoods.