If you like the E Trac, why did you get the MXT, I'm asking not being smart. I just want to know why the change?
As far as zinc pennies, when the MXT tells you it is a zinc, don't dig it. When it tells you it is a tab don't dig it. If you are only hunting coins there is no problem. The only problem is the MXT can't tell you that tab isn't a gold ring, but what detector can? I was hunting with Larry last week and he dug a 22. That's usually a tab. Instead it was a yellow and white gold ring with a small diamond. When he dug it he didn't know it was a ring. That day we were both using our V3's and you still couldn't tell.
The 6x10 has good side to side separation, it just isn't as deep has the 9.5. The MXT is fast, the ID is very accurate, it's sweep speed is forgiving and it is deep. You have to learn the VDI numbers of targets.
What exactly is the part that is giving you the problem? Then we can help better.
Rob