Hi, I'm looking to swap out the speakers in my closed back 2X12 cab for my Fender 65 Blackface Bassman. I'm not too familiar with speakers and speaker combinations, so any of your recommendations would be highly appreciated. I am looking at getting Celestions, but I'm not sure which ones and/or which combination of celestions would give me a good amount of clean headroom, tight bass response, and a smooth breakup. Can someone also tell me if I'm supposed to get 8 ohm or 16 ohm speakers? Again, I don't have any experience with speakers, so any of your advice would be helpful. Thanks so much!