I've written a quick article on the exchange of incomplete transactions. We currently use these for offline signing and multi-signature. Feel free to read this on Medium, and comment on it here.
https://roger-taylor.medium.com/on-incomplete-transactions-273b214267eb
[ Please do not tip this message, ElectrumSV does not take donations which would include tips, if you want to encourage more development-related messages tip anyone who responds with a comment that you like.. ]
-- rt12