You're right about my placement of Space after TF. My FX loop setup goes like this: Send >> PF >> TF >> MF >> Space >> Return. I've got a wah and a compressor in front of the amp, too, sometimes also a boost or OD, but that depends on which amp(s) I'm using.
In my experience, I don't really have any problems with presets competing with each other and I don't usually stick to basic delays or basic reverbs. I know what you mean about the TF being very rich and full. If anything, Space is even more so. But, they really don't run over each other, which is really a compliment to the quality of Eventide's algorithms. When using both, they still retain all of their individual character. While there are a few places they could overlap (I'll include some examples below), both pedals have so many options that it's really easy to find something different for the other to do without having to resort to basic effects.
For example, I wouldn't use Reverse (reverb) from Space with Reverse (delay) from TF, but they're not the same effect, either. I usually pair Space's Reverse with a longer delay from TF or TF's Reverse with a "straight" reverb from Space (BlackHole) or maybe something else entirely (Shimmer).
ModEchoVerb from Space is really the only other algorithm that has a delay in it (not including pre-delay in the reverb algorithms, but that's different). When I use that, I usually have the TF set to either a doubling type short delay or a very short tape delay with higher settings of wow, flutter, and drive – more of a character delay. If I do use a straight delay in the TF, it's set opposite to the one in Space, one long and one short, or maybe kick the TF on momentarily to accentuate certain notes or phrases.
I really don't use TF's MultiTap as a reverb, although it can do that.
It's also been my experience that the modulation effects in both the TF and the Space aren't doing the same thing and work really well together. For me, this holds true across the entire line.
For an extreme example, it's not terribly uncommon for me to use a MicroShift from PF for width, a ModDelay from TF for depth, and a Chorus or Flange from MF for motion. In that case, I probably wouldn't use ModEchoVerb from Space, but any of the modulated reverbs (which only modulate the reverb tail, not the source) would still be an option. It might seem like a complex mess on paper, but in practice, each pedal's modulating a different part of the source.
Sticking with just the Space and TF, even if both are set to presets including modulation, the TF modulates the repeats and Space modulates the tails, but the source remains dry (although with short delay times, that might be difficult to hear).
I've had more problems between the PF and the TF. It's easier when I use the PF as a straight shifter, but there are a lot of really cool sounds when incorporating the delay available in each shifter. It's not like it's difficult to find a suitable delay from TF in these cases, it just takes a little more thought.
Anyway, I didn't really mean to be so long winded, but I hope I've shed some light on how I use these pedals. There are so many options and I'm sure there are many more ways to use them than I've found so far.