To be entirely honest, they could have launched this on Channel 4 itself. It's not like they have anything going on at the time of day anyway other than repeats, so why not go for a potentially bigger audience? I get that E4 is the comedy station but still.
Personally, I would run it on C4 between 11 and 2ish, maybe 3. Also, I would run it on Saturdays as well as Fridays. If you don't want it too close to the other programming, maybe run the first hour on E4 and then put the rest on both. It would definitely get more ratings in my view at least. There is also the problematic factor that most Adult Swim shows are already available on Netflix to begin with. Sure, not everyone owns a Netflix account, but most people who do and want to watch the sort of stuff Adult Swim puts out would already have seen it. Ultimately, even more so when you realise that they're available on All 4, it's a hard sell for an overnight strand.
Mods hate me a bit less than before.