Heard Cream at the Back Bay Theater in Boston, April 5, 1968. Good friend of mine was an usher there - a highly coveted job. When the curtains opened the stage set had GB in middle, Jack on left,, and Eric on right. What was stunning was the amplifiers/speakers on stage - 4 double stacks of 100 watt Marshall amps on either side of GB!! The typical club scene at the time featured guitarists equipped with perhaps a single 50 watt Fender Super Reverb combo, or Fender Bassman with separate amp / speaker case. Seeing 16 speaker cases on stage was mind blowing! We thought - wow, this is going to be LOUD. The roar that the band produced blew your ears out (house PA systems then were primitive). That pure Marshall sound is never duplicated with today's tonier amps and house PAs for volume.
Although the YouTube recording features 'Sunshine' as the opener, I somehow remember that they played 'Crossroads', in which Eric played 10 verses of solo before the first vocal. Perhaps a different concert.