Looks like a VERY nice build. I especially like your last shot, which looks like a hand mysteriously emerging through the tabletop from another dimension.
In my opinion, the slightly larger pipe should be no problem at all. Theoretically, it would shorten the overall length just a hair because of the "end correction", but we're talking a small fraction of an inch! In reality, it won't matter.
Be sure you put the fuel feed point right in the center of the intake, just inside the flare, not the lateral feed used in the original prototype. And, remember that Eric claims it is better NOT to put any pinch in the intake pipe - keep it a full circular section over its whole length for best results.