Thanks for the help.
This all seems a little confusing to me. The transaction has already been pending for a few days now and I'm in no need to spend it so I guess I can just wait a little while longer for it to be sent back. A Dynamic Fee with a 110% multiplier should do the trick on the next send, though.
How much more per kb am I really paying if I use Dynamic Fees and I max out the multiplier to say 150%?
It depends, for dynamic fees electrum guesses what the best fee to pay is based on how many unconfirmed transactions are in the Bitcoin network at any specific time. If the network is quiet electrum guesses a fairly low fee, and if the network's busy electrum guesses a fairly high fee.