How much head space for primary??

I just bought a Stags Leap Merlot wine kit to make for my wife. I was wanting to find out if I would be okay using a 6.5 gallon carboy for a primary. I have never made wine before, so I don't know how active the fermentation is or how much krausen forms during fermentation of a wine. The yeast that came with the kit is Lavlin Bourgovin RC-212. I would rather not have to buy another bucket if I don't have to, but I also don't want any major eruptions from the carboy.

no problem. you wont have any krazen with the wine at all. maybe a little but not enough to be a problem

Thanks for the quick response.

I have another question. Is Star San okay to use for winemaking, or should I stick with sodium metabisulfite like the directions say?

As far as sanitizing goes, yeah star san is cool

Do the instructions say what size primary to use? the kit I got says an 8 gallon primary. It really doesnt need to be that big but for what it cost for the kit it seems silly to screw it up because I didnt have the right size $10.00 bucket. If it makes 6 gallons a 7 or 7.5 gallon bucket should be fine. This way you dont splash out when you degass or add stuff and stir.