It is worth underlining the fact that the idea itself did not immediately lose, but it put Black in a less desirable position developmentally versus the main line, essentially a tempo down on developing the kingside, which gives White some additional tactical possibilities. What did lose more or less immediately - but not obviously so - was my decision to castle queenside a few moves after White's aggressive response with 11. c4. From previous analysis of similar games I knew that this was a relatively risky decision, but as far as I could see, White could not directly exploit it with good defense by Black. Unfortunately, I was wrong and the decision doomed me strategically.
The game is unusual in that respect, as normally a single error is either an immediate blunder (obviously non-recoverable) or can be recovered from later on with better play. Here Black is put on an inexorable path of doom, which only materializes a number of moves later. My opponent deserves full credit for taking the time to work out how to do this, although he missed a chance on move 19 to more quickly put me away.
In this case, although the opening experiment was a failure, it's helped give me more insight into the opening and middlegame dynamics for future use in the main line with an immediate ...e6 (and more confidence in that being the best way to proceed).