I think they are kind of the same in Welsh as it’s: “Byddwn well gyda fi” = It would be better with [for] me. I would use this phrase to mean both better and rather. For a more preferential rather I would simply make it present tense ’ Mae’n well gyda fi’ = it’s better for [with] me and make it a general case.
Talking of which, this came up on Y Wenhyseg Twitter account yesterday: The young couple who run it found this phrase:
‘nabyddsat ti ddim o hi’ for You would not recognise her
Admittedly “nabyddsat” looks very Gwentian/Wehwhyseg but I wonder if a toned down **Nabyddet ti * might be used for “You would recognise/know” (based on nabod). It has a similar inflected ending to hoffet ti for you would like.
Gareth King (Modern Welsh p.201) has the following intriguing snippet about (ad)nabod and other verbs based on -bod:
“…usually have stems in -bydd-/-bu- … There is considerable uncertainty about these among native speakers, and periphrastic forms are often preferred in speech.”