jmp81sc, it appears to me that you have more than one problem....scratchy pots, channel interaction question, bad signal in some situationsand the trem function. The fact that Re-routing a wire or two as you report in an earlier post had a positive result might indicate a lead dress issue...or more than one. Because you have built this circuit in a chassis that is totally different from the original, you have given yourself the task of dressing leads without a known guide. I would lift the connection the trem from the biasing circuit....jump the bias voltage directly past that Depth control after disconnecting the trem circuit from that lug on the Depth control. This would allow you to see if that circuit is having a negative effect on the signal. If not, then resolve the ‘straight’ signal issues before bring the trem circuit back into play. I might even life the plate voltage supply to V3 so as to get the voltages completely out of that circuit’s wiring.