Tax Accounting for Making a Significant Charitable Contribution

I have made a charitable contribution (in excess of $5,000) of Model A Ford parts and tools to the Model A Ford Museum.  I imagine that I would have to submit a Form 8253 with my return.  Because the number of pieces involved is no doubt in excess of several hundred, I have made up an Excel spreadsheet outlining the parts, their cost, current vendor selling prices, and their condition.

 

As I understand the procedure, the Museum will have to sign off on receiving the parts on the form.  Another section of the form also asks for an appraisal.  I know of no one in the industry that performs such services.  There is a well-known technical writer for one of the nation's two Model A Ford magazines.  He was involved in the transfer of the goods, and I could possibly ask him if he would be willing to give an overall assessment of the value (but not of each and every part).  Would he provide a letter, or simply write in his summary assessment on the form?  Since this is large tax return (well over 100 pages), can I still e-file the return?  Would a separate letter/form be mailed to the IRS simultaneously?

 

Thanks for any thoughts!