Most guitar guys I work with use 25 watt combo amps. One guy told me the only time he needed a 50 watter was when he played on a huge stage at Summerfest (huge music fest with huge stages). The PA guy will mic 'em and take care of the rest. If the crowd can't hear the guitars, it's the PA guys fault pure and simple. Bass players need about 10x more of what the guitarists have, so with you at 300 watts, you are barely/not quite there with 2 guitarists running at 25 watts each. You'd be better with at least 500 watts, but it also depends on your style of music, the efficiency of cab, and other variables. For good stage presence and front row sound, each guitar guy runs a 25 watt combo, and you run at least 500 watts as a combo or stack. The PA guy will take over from there.