Re-Pointing sand stone wall with tight joints

[dannyonthefarm]

Hi I need to re-point the frount of my house.

It is built of sand stone blocks, the problem I have is that some of the joints are very tight almost stone on stone.

I was thinking of making the joints a bit wider with a grinder but I am unsure if this is the right thing to do?

Also in a couple of places the joints are very deep is it ok to just fill these in one go as I do the pointing or should I fill these deep bits first and leave space for pointing when it has dryed?

Cheers

Danny