I'd scan the various films on which there are the problems you describe. What you mean by sprocket streaks and what we think you mean may be two different things. A picture should clear up any misunderstandings.

As you have described your process I like Roger am at a loss to point to any fault but of course there has to be one or more to ruin the film.

Apart from streaks which I assume( there you go, an assumption on my part which may be wrong) to be black streaks stretching for the sprocket holes to areas within the negs, how do the negs look?

Without a scan to see we are "punching the air"