Paul - DON'T use the 9fr spacers in your brood chambers.  They are made for
honey-supers, and what they do is evenly space out the 9 frames across the
box.
 
As noted in my previous message, the manner of spacing 9 frames in a brood
box is different.  They are nearly as close together as if you had all 10
frames, and space is left over at the sides.
 
If you use the metal spacers, the brood combs will be spaced wider than 1.5
inches, not to mention the spacers will constantly be getting in your WAY.
 
You can't slide frames back and forth if you have the spacers, nor clean
off the frame rests.  They weren't intended for brood chambers.
 
Thay can be handy for the supers, as you don't have to fuss with spacing
out by hand.  I used to have quite a few, but really, after a few years,
there was so much propolis built up, and I couldn't clean off the frame
rests, that I ended up just ripping the spacers out.  Now I just eyeball,
and as I said, space 8 super combs evenly across each honey super.
Accurate spacing in the supers isn't as critical as in brood chambers.
 
Hope this is helpful...      JG