"You have several options.
1) Attempt the Scottish words and the accent.
2) Keep the Scottish pronunciations but sing the rest in your own accent.
3) Attempt a wholesale Anglicising.
4) Don't do it."
Err, personally I like number two over and above any other option, both to listen to and to attempt for myself.
Dialiect, or regional nuances in language, isn't quite the same as accent and doesn't IMO feel as 'faked'. But yes, of course it's all down to individual preference, of both the singer and the listener.