Thank you for taking the time to respond. What I'm actually after is: vector A to become vector A' over t seconds and vector B to become vector B' over t' seconds (different amount of seconds), but eliminate the sharp visible switch of direction when combining the two (after one reaches it's end point before the other), which at this point (unless I'm mistaken) does not appear to be mathematically possible (can not advance at different rates and complete at the same time (without adjusting distance)).

This might be the best answer I've ever seen written on a stackexchange site. It's extremely well written, descriptive, and explains why I was having the issue I was having AND includes a solution. Thank you for this! It did indeed resolve the stutter, and now it will no longer be haunting my dreams :)