Recommendations for a Crate Blue Voodoo BV6212?

Hi,

I picked up a Crate Blue Voodoo BV6212 really cheap because it was having problems (big surprise) and I'm a sucker for projects like this. So I fixed the problems but the previous owner pulled the original speakers threw a mismatched pair of a Marshall Gold and an old, what I believe to be a, CTS. The Marshall seems much louder, but the CTS sounds better. Anyway, I was thinking of throwing in a pair of ET65s but I've heard of others mixing with a Retro 30 or a Vintage 30.  I'm concerned about two different speakers giving different sounds to the audience depending on their location with this 2x12.  Is this something to worry about?  Am I better off staying with two of the same?  Any other recommendation?

Thanks!

Lee