Another program letter question .....

My plane is registered experimental and I have not been sending the
annual program letter to the local FSDO. I plan on starting but have
a couple of questions:

1 - The original airworthy certificate was issued by the Reno NV FSDO
and the first two owners sent the letter there. I am in the SLC UT
area and am wondering if I can/should send the letter to the Reno FSDO
or do I need to send it to the SLC FSDO?

2 - If I send it to the local SLC FSDO should I include a copy of the
original paperwork?

I will be contacting the SLC FSDO next week but wanted to solicit
opinions here first

Thanks in advance

Ron Gleason