They look like 2x15's with the JBL D-130 speakers and silver cones. Could be D-140's too. Dick Dale likes the 140's.
Sounds good! The whole backline at the Newport Pop Festival was Fender, unless Hendrix had some secret sauce rigged up somewhere. There is footage of the gig, and Hendrix looks like he is standing in front of a silver wall.
Interesting to hear 'twang' mentioned in the context of Hendrix, as he seems to have been fairly consistent in keeping the twang out of his tone. If you see pictures or video of Woodstock he is running those big curly cables between everything, including his Univibe/wah/fuzz setup. No patch cables! Again on the Metro Amps forum somebody reckons he had about 90 ft of coiled cable from guitar to amp, and the cumulative capacitance of that lot would go a long way to dial out the twang.