one thing would be nice is to provide a "upload token"
so instead of a shared (this is a massive security risk) account login, a receiver can go to the vrc website, log-in and generate a upload token.
(to generate it would need to get the sender's account embedded in the token's authorization and it being a onetime/oneday use item)
And then in chat relaying the token.
Then when its time to upload instead of "Build and publish for windows"
it has a "send avatar to friend" [PASTE TOKEN HERE]
Step1: users agree to get avatar
Step2: receiver goes to vrc.com logs in and navigates to avatar page
step3: receiver goes to "receive avatar from friend"
step4: friend in list is picked out [KUNG VR]
step5: website goes: We have generated a single use upload token, send this to [KUNG VR]
(on a sidenote, this could also cause a flag on KUNG VR's account (web or sdk) so the upload dialog will go "Stabby has sent you a upload token, click here to use it" )
Step6: Sender goes to upload page on SDK and sees a button "Send avatar to friend"
Step7: Sender pastes token (or this is handled internally so the user selects the token in SDK GUI)
Step8: Normal upload process resumes