It’s sort of a matter of what works best. Mostly likely the TF has buffered and isolated outs. Whether they’re as good as the Lehle is going to be up to you. I would connect the TF direct and if you experience no ground loops, signal loss or loss of highs then that should be fine. However, if you do have issues and when you use the Lehle things sound better than that would be the way to go. The Lehle devices are top notch stuff and designed to stop many of the issues with dual amp and maintaining signal integrity.
The main thing is use your ears and not your eyes.
