Very cool butt welding technique

I have a bunch of bodywork to get into.
My problem is that my machine came designed/set up to run 0.030 or 0.035 wire
And even then I have to change the contact tup when I change wire size.
I want to switch to a spool of 0.023" wire, once I get into the bodywork phase/ that's what I have at work with a smaller series welder. (I don't do bodywork at the job but I do so alot of exhaust welds)
Can I do this just by changing the contact tip? Or do I have to change drive rolls, the gun liner as well?
I have a millermatic 185 that I bought brand new back in 1997-98.

I burnt out 2, 110v welders before that and decided then I didn't want anything less than 220v powered machine. Never a minute if problem since I got this bigger machine. But in the last handful of years since miller and Hobart came out with ~"135"-ish sized 110v machines they seem to hold up better than the first 2 mig's I had which were 110's. We have a millermatic 135 at work that does most of what I need, if I need bigger I go to the IDOT side of the building and use their millermatic 250.
I wish I could borrow the 135 and bring it home on weekends but working for the state isn't what it was years ago. So I can't.

So can I set up my 185 for the smaller wire for my bodywork?