Trying to weld, I’m terrible!

You will need an 0.025 inner liner and use 0.023 tips for 0.023 wire. A 0.035 inner liner for 0.030 wire will not work.
I have found this NOT to be the case. I use a Millermatic 210 and have used both .035 and .023 wire by simply using the corresponding feed rollers and contact tips.