CO method to use for the middle of a project

I have just started this sweater.
After the initial cast on, which is mostly for the sleeves and back, I knit 25 rows back and forth before joining in the round. The instructions say:

CO 6 sts, join to k in the round. PM to mark start of round.

Now, from the way this is going, the 6 CO and the join will be in the front of the neck area. The CO is after a RS row is finished.
So my question is: what is the best CO method to use for this? I think my only options are knitted CO and reverse loop. Do you know of others?
It seems like it will be very visible, although all this is done with the MC and the CC for the neck is put in at the end, so maybe it covers it. I haven’t gotten very far yet, so I can’t picture it.
Thanks for all your expert help.

A knit or a cable cast on will work well here. And yes, it looks like the finishing around the neck will cover the cast on anyway. Either of these will provide a neat, sturdy cast on.
Very pretty sweater pattern.

If it’s only a few stitches I sometimes use backward loop, too.

Thanks for your help. I’ll probably use the knitted cast on, since I know how to do it.