I have used DIM PRO for a long time, but never tried to tweak each sound using the sections and controls and would like to try making some modifications.

Aside from the documentation included with the synth, the best resource is Simon Cann's book "Cakewalk Synthesizers: From Presets to Power User—Second Edition." It covers all the synths except the Rapture Pro/Session.
 
There are a variety of resources available on the web regarding sfz files. Most of that data is relevant to DPro.

Simon Cann has made a free download package with a PDF e-book that contains the chapters that his editor cut from the printed book "Cakewalk Synthesizers: From Presets to Power User—Second Edition.".
 
The e-book contains chapters 14-29.
 
See chapter 27 - Creating Sounds in Dimension and Dimension Pro for a few lessons.
 
The download link to the zip file is embedded in the first paragraph on this page, under the text "click on this link".
 
https://noisesculpture.co...ynthesizers-downloads/