About to buy a used Epiphone Valve Junior head and cab but the seller has given me the option of keeping the stock Eminence Lady Luck speaker or is willing to switch it out with a Celestion Greenback. I won't have a chance to A/B them so I'm looking for some opinions. I play a Fender US Strat with Air Norton / Chopper / Tone Zone rails pickups - shooting for a standard rock tone (my pedals will do alot of the heavy lifting). Just wondering which speaker setup has the potential to work best? Thanks in advance.