I've got a chance at picking up a Celestion Greenback for cheap. I've read where guys have installed them in their Classic 30's but I'm a bit leary. 30 watt amp, 25 watt speaker......you get the idea. Has anyone here tried this and if so what kind of results did you get? What kind of tone did you get from the OD channel? How about clean headroom? Right now I can turn the clean channels volume up to 6 with the stock speaker before it starts to get any breakup. Any info would help. Thanks.