I suppose it's not a good idea to use

two different brands/material of needles that are supposedly the same size in one project, right?

In the pattern I’m doing, you CO first onto size 2, knit 3 rows, then change to size 3s. I’ve been CO to my size 2 Boye interchangeables, then for my size 3, I’ve been using my bamboo Crystal Palace circulars. Right now my sleeves are on them.

I thought about CO for the left front on the Boye size 2, then just changing the tips to the 3s. The Boye tips are just the smidgenest bit smaller than the Crystal Palace per the holes in my needle sizer. I also thought that since one was bamboo and one was metal, that might change my speed and thus tension a bit too.

And it’s not like I can actually simultaneously knit the sleeves and fronts anyway, so I could wait until the bamboo 3s are empty again.

I can’t imagine that it would make that much difference. I switch from metal to bamboo when I’m decreasing for hats and sleeves and such, and I didn’t notice where it happened.

If you’re really that worried, you could compare them using a knitting gauge. Put one in the corrct hole, and then the other. If there is a glaring difference in size, you can notice it there. Since it’s only for 3 rows, unless the difference is so much that the tip is actually a different size {it does happen occasionally}, I wouldn’t worry about it.