Wiring toroidal transformer in parallel

[Muzzer]

They look pretty good. I don't think RS sold those when I did mine. I used a Finder one which costs more https://uk.rs-online.com/web/p/timer-relays/0221086/

Yes, that's how they work. The nice thing about an NTC is that you don't need to worry so much about the value. If you aren't getting nuisance tripping of breakers, it should be fairly straightforward.