Can't "wrap" my mind around this

Help! I’m sure the answer to this is patently obvious to everyone except me, but I’m going to ask it anyway :lol:

I have some gorgeous Laurel yarn from Schaeffer that I want to use to make the Temptation Wrap. The yarn knits up at a slightly smaller gauge, so I want to add some stitches when I cast on to increase the width a bit. The pattern says to cast on 39 stitches which includes 3 knit stitches on each side for the border. So, that gives me a lace pattern of 33 stitches. If you look at the pattern linked, can you tell me if I should add stitches in increments of 2 or 3? For instance can I cast on 9 extra stitches for a total of 48 or should I go with 12 extra stitches for a total of 51? Does that make sense? :shrug:

I throw myself at your feet begging for an explanation, as I am dying to start this little wrap this evening while I try to keep the dog from jumping out of his skin during the fireworks :lol:

The lace pattern is a multiple of 3, so you can add any amount of 3’s that you like to get the width you want.

See, I knew someone like Ingrid would be able to swoop in and easily answer my silly question! I thought it was a 3 stitch lace pattern, but it seemed so obvious that I figured I must be wrong! :lol:

Thanks so much!