A wedge isn't even necessary for DSS stacking. This IIS user Wayne Anderson was doing it for ages without a wedge in Alt-Az and DSS .
Here's a collection of his wedge-less imaging and processing results.
Here, which was 2 months or so later than the first, he shows M42 and ponders using a wedge sometime in the future.
He also mentions some DSS settings which might help Bruce's stacking, as well. It could be just a little thing like forgetting to tick "register all frames" or something.