I just measured the deluxe extension cab I had made with a 4x10,2x12,1x15 baffle. It's nearly dead nuts to the overall dimension of the SR cab. While I won't achieve more headroom it may be a fun experiment to play with some 10's. Looks like the reverb tank is similar in size to the SFDR. Trying to get my head around pricing some speakers that will give a good interpretation of that fender shimmer with my SFDR. So far looking at Weber 10f150, 10a125. If this deluxe ext cab sounds good with my SFDR I may just grab a quilter for bigger cleans to use with this cab. Not sure just yet tho..