O-ring for oil cooler pipe in oil pan

[volvodork]

OK...so I'm replacing all of the O-rings in the oil pan on my XC70 and got the Victor-Reinz kit to do it. Great write-up on how to do it on this site BTW. BUT... I haven't got a definitive answer on all of the searching I've done but it seems that the o-ring that goes on the tube where the bolt is to hold it down in the pan is NOT in the kit?? all the other O-rings in the kit seem to either be just a little small or too big. I don't want to "guess" and have it not seal properly once this pan is all back on.
Anyone have any tips on which o-ring to use here or do I have to go the dealer route???
JD