Re the SS 316, I've just taken the resitivity figures and run them for full size half-wave dipoles in EZNEC. For 3.5MHz, copper wire of 0.5dB better than 316 grade stainless steel, at 7MHz copper is 0.35dB better, at 14MHx copper is 0.25dB better and at 28MHz copper is 0.1dB better. This is comparing copper before it has corroded against 316 grade stainless steel. The differences wouldn't be noticeable. Interestingly though, I understand that the losses with 316 SS would be greater as wire length increases, and would also be greater as frequency increases. In the case of full size half-wave dipoles, the losses through increase frequency are offset by the fact that the wire runs are shorter. But strangely, when I model a 44ft doublet, which is short on 7MHz, the loss of SS 316 wire vs copper is much higher - about 0.8dB (compared with 0.35dB difference at 7MHz for full size dipole).