Thanks Scott.
Unfortunately those two reflectors take a gird that is 13 inches in diameter, so I would need one at least that big for your method to work.
Just checked B&H, it appears all the 5 degree grids are 7 to 8 inches in diameter.
Maybe if I am gridding the light that much, it would not make a difference too much what reflector I was using.
I'll have to test this. Magnum probably will be the same as a normal reflector. Narrow beam produces an unique look though.