I see. My issue is spacing. I tend to compress the forms. More practice for this script.... Perhaps this is not pragmatic for me, as am required to write very compressed and not small.
Hello Inky. You have hit the nail squarely on the head here, because one of the defining visual characteristics of textbook Spencerian is a horizontal emphasis. This is driven by the connective slant and causes the writing to spread out along the line like no other script. You can easily compress it by steepening the connective slant, but you lose the distinctive character of the style. This is why Spencerian is generally written small, and it therefore follows that a sharp nib (untipped!) is highly desirable.
If the size of your writing is not negotiable, it might make sense to go back to Platt Rogers Spencer's style of writing, which is considerably different but has its own charms. As you suggest the Compendium of Semi Angular Penmanship Book 10 is one of the best sources for this, but for illustrative purposes I've attached some doggerel by PRS.
If you do pursue this line, Alexander's point about breaking the letters down into the principles is still enormously important - in fact it seems to me that it's the key to swift progress. Interestingly, the principles pertaining to minuscules in the Semi Angular book are not the same as those used in the later books - at all - but it's the process of analysis which will help rather than the specifics.