Before someone says it, no, I don't plan to rebuild a dual coil into a single coil. 
I'm not totally sold on the dual coils and I have Mini Protank 3s (IMO, they're overkill in these), T3Ds, & Evod 2 w/ glass that I'd like to try to use with a single coil head instead. As the area of the dual coil (below the rubber chimney grommet) is taller than their single coil counter parts, how can I use a single coil successfully? Do you just use a 2nd rubber grommet to fill in the gap, or will another vendor's coil fit (and work!) in that larger space?
Thanks!
I'm not totally sold on the dual coils and I have Mini Protank 3s (IMO, they're overkill in these), T3Ds, & Evod 2 w/ glass that I'd like to try to use with a single coil head instead. As the area of the dual coil (below the rubber chimney grommet) is taller than their single coil counter parts, how can I use a single coil successfully? Do you just use a 2nd rubber grommet to fill in the gap, or will another vendor's coil fit (and work!) in that larger space?

Thanks!