Please PM me and suggest your email ID in that PM if you want my letter template.
Additionally depending on how you package your case and what kind of papers (those seven) that you have, you may wanna apply for both NIW and EA.
I think you are better off applying for I-140 first because if you are approved at 140 stage, after that retrogression can only cause temporary grief. Unless you screw up bigtime your 485 approval will be a done deal after 140 approval whenever visa numbers become available (and you dont fall in the name check black hole, heavens forbid)