Threshold Fet 10E bi-amping question

I am currently bi-amped with 2 Threshold S-300E Series II amps, and a Threshold Fet 10E pre-amp. Since the Fet 10E only allows 1 balanced out, and 1 RCA out, to bi-amp, I have to use both. I was in touch with Jon Solderberg of Threshold, who updated & refreshed all of my equipment, new caps etc... And he said he thought the Fet 10E HL should be able to drive both amps. I've since lost touch with him, but had a tweeter go out on my B&W matrix 802 Series 3 speakers. And now I find no way of contacting Jon. I had one amp running the mids and tweeters, and one running the bass drivers. Due to all the hurricanes we've had in Florida, everything is unhooked and stored safely, but I am dieing to put the system back together. Am I better off running the tweeter/mid amp on the balanced input amp (Tice XLR crio treated inter connects) or the RCA amp (Audio Quest Emerald)(both identically matched amps)? The tweeters were a bit bright to me before, and I don't think the Threshold gear is. Unfortunately, I can't remember how I had it set up last. I would like some input before I buy the new tweet and hook it up again. Also could you please give me the correct replacement tweeter model number?? That would also be a huge help. Thanks for any advice you can give me. Tom