Personally, i set my electrum preferences towards fees as:
- use dynamic fees => yes
- edit fees manually => yes
- enable replace-by-fee => yes
This way all bases are covered:
- electrum calculates what he thinks is an optimal fee
- you have a slider to edit the fees
- you can change the fee manually, overriding any automatic or slider setting
- if you still manage to mess up, and add to low fee, you can use the RBF functionality to edit the fee even after the tx has been broadcasted.
Apologies if being a pain but I dont see the option to set that when in sending tab. Is just a place for pay to, description and amount.
I'm using it on a raspberry pi if that makes any difference.
thanks