I have a question for any owners of Ampeg B15N double-baffle cabinets who might be willing to remove their grille baffle: How thick are the spacers that are attached to your speaker baffle? Gregg Hopkin's Ampeg book says they are 3/8", as does Jess Oliver. I am asking the question because I have recently come across a couple of cabinets that had 1/4" thick spacers. I asked Jess about these and he said that Everett Hull would sometimes make design changes for, essentially, no good reason. Some of these changes included smaller ports, similar to the B18N, as well as stuffing some of the ports with blocks of foam rubber. I'm just curious to see how many cabinets out there have the 1/4" spacers. Thanks!