I wouldn't underestimate a 22W valve amp. It can be pretty loud. In a stage gig, I could hear my 18W Laney over the onstage mix monitors when turned up, that too when the amp was just in a pushed and not over driven state.
Besides, increasing the number of speakers needn't be for volume alone. The bass response improves a lot and the tone becomes a lot more thicker as the 4 speakers work like a chorus effect due to minute delays in the actual physical movement of the individual speaker cones.
-- My current rig
Guitar: '98 MIJ Ibanez RG520 QS w EMG 81/60
Amp: Laney LC15R Tube, Fernandes 20W SS
Pedals: MI Audio Tube Zone Overdrive, Boss OD3, CS3, MT2, HM2, DS2, CE5, DD7, TU3, Beta Aivin DD2 Delay, Dunlop Crybaby 95Q, Stranger Vol Pedal, BBE SupaCharger
Others: Yamaha RBX 374 Bass, Yamaha MM-6 Synth, M-Audio Fast Track, Shure SM-57, Heet Sound E-Bow Plus
Wanted(pm if selling): EB VPJr/Boss FV500L,Ibanez w Original/Lo-Pro Edge