In only when , there is a sense of urgency, a slightly more 'involved' writing. It was only when is by comparision more 'relaxed' writing, more like someone is recounting something to someone. Which is grammatically correct?

Or i can do only so much in this time. I am from bangalore and people here tend use the word only to emphasise something in a sentence. We are getting that only printed. What is the proper way to put it? The oxford english dictionary defines but only (which can also occur as only but) as meaning ‘ (a) only, merely; (b) except only’, and comments that its use is now poetical.

The oxford english dictionary defines but only (which can also occur as only but) as meaning ‘ (a) only, merely; (b) except only’, and comments that its use is now poetical.