[Is it worth copying files before sync? ("pre-seed")]

I am in the middle of a large sync operation (~900GB) and was wondering if it's worth it to copy files into the synced directories to speed up the sync? I have a majority of the files copied to another drive, just not synced. Will this speed up the sync and sync will notice the files already exist?

[Should I SyncIgnore .git directories?]

I am currently using BTSync to sync github clones on my office machines and home machines. I am wondering if I should ignore .git directories to make syncing less corruption prone. Every once in a while (or when significant time elapses between office visits or vice versa) I always encounter issues where a bunch of files have .!sync.SyncTemp suffixes, or git reports some copies are in conflict for whatever reason.

Just looking for a shortcut so I don't need to go find out how git works internally more than I already need to. I have a feeling it would be cleaner to allow each .git dir to maintain each location but wonder what other issues that might create.