Selvedge stitch? help!

I’m doing a project (with the imfamous raglan seams) in seed stitch - I’d like to plan ahead and put slevedge stitches at either end to help me with seaming later, but I’m confused - my seed stitch on both RS and WS is *k1, p1, repeat from *

I’ve read that selvedge stitches work best when they are knit on RS and purled on WS (like basic stockinette) - but do I need 2 extra stitches on each side to make this happen, or just one?

with just one, I imagine it would look like this, on RS, I knit 1, *k1, p1 to 1 stitch, K1,
on WS, I purl 1, *k1, p1 to 1 stitch, p1

would this get me what I need? or do I need to have K2, seed pattern, K2 on RS, and p2, seed pattern, p2 on WS


The selvedge edge will be used for seaming when you are done, so I would do it like a garter stitch, rather than a stockingette stitch, which has the nasty habit of curling. Even 1 extra stitch at the end of each row will work, just always knit it, or always purl it, to get the garter effect.

thanks for your help - i will give it a try