New cast iron cookware question

Been thinking about getting a new cast iron skillet, have a couple of old ones but they're very small. Kinda want one big enough to really do something with. I won't use it much, so I don't need expensive stuff.

The new stuff I've looked at is quite rough on the cooking surfaces, even the new Lodge stuff. My question is - would it be OK to smooth the cooking surfaces with a sander/grinder before I season the pan? Or should it be left rough? I don't want to buy one and ruin it. But my mom's old skillets are as smooth as a baby's butt.

Yeah, we recently had a thread and the cast iron gurus all said they sand down the new stuff.

I thought so, but couldn't find that.