In the settings there is the tab "Default of Machines". It would be nice, if you can set multiple default machines and it takes the first, which is possible.
For Example:
- Crafting:
- - Electromagnetic Plant, where it can be used
- - 2nd Prio: Assembling Machine
- Chemistry:
- - Cryogenic plant, where possible
- - 2nd Prio Chemical plant
I guess there are more examples. Especially with mods. Also there may be needed more than 2 priorities.

The same could be used for productivity / speed modules but that's not important for me.

In the settings menu there could be the possibility to have an add button and move up/down.
In the recipe selector it would be nice to have it as new lowest prio, if you hold shift. If you don't hold shift replace the default machine.