Paul
Are you only having trouble getting savings on the pine end grain, or is this replicated on other wood types? Soft pine can be impossible to get shavings on.
A few notes.
I think that regrinding the bevel angle to 20 degrees is inappropriate. Firstly it is unrealistic since a bevel this low will not last. Secondly it is possible to take shavings on soft wood end grain with a high cutting angle. I interchangeably use a HNT Gordon Trying plane (60 degrees), LV LA Jack (37 degrees), and a LV LA Smoother (37 degrees).
Here is a HNT Gorgon on medium soft Mahogany:
I consider that the key elements to successful shooting are a sharp blade and a fine cut. The size of the mouth is irrelevant.
The ramped shooting board that I built some years ago was based on the ramped board of Michael Connor, which was introduced to me by Terry Gordon (of HNT Gordon). Up until then I was using a flat shooting board. Both types work but I find the ramped board is (slightly) smoother in the cut.
Regards from Perth
Derek