I think that the best way to run the TimeFactor with the Space in parallel is the Stereo X-Blender (SXB-1) by Xotic Effects Custom Shop:
watch the videos on this link and you will understand how you can run the Eventide stompboxes…
-don't forget to enable the Kill Dry to both stompboxes!
another solution is the Mini Line Mixer by RJM:
you can split the signal from amp's fx-loop Send with a Y cable and the one cable will go to Mini Line Mixer 's 4/Dry input and the other cable split again to Y cable with
the one goes to TimeFactor's left/Mono input
and the other to Space's left/Mono input.
From the TimeFactor's left/Mono output to Mini Line Mixer's 1st input
and from the Space's left/Mono output to Mini Line Mixer's 2nd input.
Lastly,from Mini Line Mixer's output to amp's fx-loop return.
If you have any true-bypass looper with at least two loops,you will avoid all this Y cables!
from fx-loop Send to true-bypass looper Input.
put each stompbox to each loop…and from there you can enable or disable the stomp you want… and from there you can feed the Mini Line Mixer's inputs.
the output from the true-bypass looper to Mini Line Mixer 's 4/Dry input.
and from Mini Line Mixer's output to amp's fx-loop return.
You can ask mr.Ron Menelli,the founder… for better solution here:
He is very nice guy and pleasant to talk!
other solutions are the Suhr MiniMix II and the Lehle parallel L,but i don't think that's your thing!
Personally,if you already have true-bypass looper,the best way is the RJM mini line mixer. If you don't … the Xotic Stereo X-Blender!