An hour or two of direct morning sun followed by dappled shade thereafter would not constitute "deep shade". What you describe would actually be pretty ideal. Cunningham's White is no different than most elepidote rhododendrons. More light will produce heavier bud set, but some shade is necessary in hotter climates like Z7.

Thank you! That is good news. Are there others that may bloom better in shade? I may have exaggerated the dappled light a bit. I'm looking for a white one (or red) on the smaller size. I asked about cunningham because it is in stock locally.

If you can source it, 'Snow Lady' has a reputation for blooming well in even quite dense shade. A compact and very early bloomer but with quite loose trusses.