Is RCF L18P300 ok in 1850?

So a while back I gave some the plans for the PD1850 horn. I was unable to find PDs here in the US so I decided to go with the RCF drivers in the 186 horns. I had this guy make me 4 cabinets but he used the original plans and I have 4 PD1850 horns loaded with RCF 300s now. I used them for a job and they sounded great but when I got them back to my shop started noticing horrible rattles in them when I get into the 1-1.5kW range each. The bracing has yet to be put in the cabs (only bracing is the set by the speaker cutout) so Im hoping that this is the problem with the rattling. Does anyone have any ideas or know if this driver will survive in the 1850. I am planning on getting more built but now Im not sure if I should go with the 1850 or the 186 design.

Rob

So I talked to the guy I had building the 1850's for me. Luckily for some reason the baffle in question, the one that is the different between the 1850 and the 186, was the only one that wasn't glued in the cabinet. With some work last night at my shop I was able to get that panel out. This solved the air space issue that I was worried about and also seemed to be the cause of the vibration/rattling. I still definitely want to add the bracing as Im sure it will help in the long run but panel vibration/ resonance is pretty minimal. Now I just need to figure out if I should ad the baffle in the 186 position of just leave the chamber open to maximize airspace. I just don't know how much that little bit of extra volume will effect things, although the sub did sound god when testing.

Also, the reason I was asking on the RCF driver is that it is listed as the #3 driver for the 186 on the plans.