I recently had reason to contact Pratt & Whitney Canada re engine handling of the P&W Wasp Junior 985. The reply was prompt and concise and I was highly impressed. One of the recommendations was to shut down the engine on the ground by first going to 1600RPM then select pitch to full coarse and drop the RPM before shutting down the engine. The start up was also done in full coarse pitch until oil pressure stabilised then select full fine.
The reasons why were given in the P&W reply. From all this I strongly recommend you contact the engine manufacturer for your specific query as it minimises being swayed by old wives tales.