How to set a recipient in the CRM Send Email window via URL querystring

I need to let the user edit the email before sending, so email templates seem to be the best choice.  I love how CRM set the Regarding to my current entity.  In addition I wanted to be able to set the To: field based on a contact record.

 

MSDN - URL Addressable Forms and Views

and here:

Working With All MS CRM DataTypes In Javascript

and ultimately, I figured out the querystring parameters that allow you set a PartyList attribute (To is a PartyList - thanks to Stunnware tool for that detail).  So by adding these parameters to the original Send E-Mail link, the email opens pre-populated:

&partytype=2&partyname=John%20Doe&partyId={1FF3C7A9-D8BC-DF11-8337-005056BC7B56}