Re: Cast piling up
I am way far from a casting expert however if you are using a 28' head, leader, and shooting 20 yards of running line which = somewhere around a 90 foot cast depending on the length of your leader............ That's quite a ways in my book. Generally if I were to have a cast that would not unfurl completely I would suspect that my anchor had not been sufficient to load the rod well enough for the distance wanted. Or......... the anchor had begun to sink and too much of the energy that should have went into my cast was lost as the line was pulled from the water.
If I were having trouble such as you describe I would back peddle a bit. By that I mean that I would return to casting the distance in which I could deliver good presentations. From there I would focus on the timing and speed / energy that I were applying that was resulting in a good cast. From this 'sweet spot' in my casting I would then look to lengthen my casting distance a little at a time until all was well at both short and longer ranges.
I think many times we are caught up in the mindset that we should be ably to cast 100' just because we are using a Switch or Spey rod. More often than not reaching such distances with consistency and quality of presentation will take a good deal of work to achieve.
Do remember this if you would, I've caught some really pretty fish as the result of a fairly ugly cast. Even if you've had less than stellar results with any one cast, retrieve enough line to straiten out the jumble and fish your fly. There is nothing wrong with 50' or 65' casts when using your rod. Don't get too caught up in the thought that every cast must hit the other shore. Slow down and find your weakness and you'll be able to correct your cast. One last thing; what are you having tied to the end of your leader? Some rods and lines will just not carry larger flies great distances.
Hope that helps,