Bassman RI speaker swaps

[Blueharp1@xxxxxxx]

 What would happen if I were to make a new baffleboard for my Bassman Re-Issue, (with holes for 8" speakers)...could I simply sub the 8's for the 10's, without any additional adjustments? Has anydone tried this? Do they simply have to be the same Ohm-age?
 Or, as referenced in one of Scooter's posts (re:Kim Wilson's amps), what about replacing 2 of the 10" speakers with a single 12?" Or does it have to be a one-to-one swap?
 I'd like to hear from someone about SIMPLE speaker-swapping, explained on a very practical level (on account of that's the kinda guy I am), especially with regard to the Bassman RI.

 Bonus question: My local custom guitar shop guy is selling the Yello-Jacket tubes ($119 per pair) that allow for tube-swapping without rebiasing. Anyone try these yet?

 Thanks,
 Jeff G
 Denver CO