Good question-
I would wait for a bit.. Maybe bury 1/4th of them in a bigger pot just to be sure they don't dry out- 'Cource the roots will probably grow through the little pot & into the bigger one.. But me? I'd wait untill the new guys are 4 to 6" tall before I transplanted them.

But that's just me.

One plant is about 8" the other a bit smaller. I was just surprised that Kartuz recommended going from a 2" pot directly to a 1 gallon container. I know passion vines like room but that seemed kind of extreme. I was thinking of going to a quart container but was wondering what others do.

I also just received 2 of my plants from Kartuz and personally I do the same thing with all plants that I order and are 2 - 8" when received; I let them adapt to the light, etc. after the shipping; once I see that they have adapted I transplant them to an 8" pot; once they start growing rapidly then I transplant them to the largest pot that they will spend the summer in. which is usually a 10-15 gallon pot. I personally like to do this rather than constantly transplanting I think it reduces shock, etc. And all of my Passi's for the past 7 years have done very well this way. The only ones I did differently this year were the Square Stem Plants I put those in 1-2 gallon pots instead of the 8" pots and once the outgrow those they will go into the Largest pots. Basically I only like to transplant 2 times; once 2 days after arrival and then again to their permanent Pot. But that's just how I do things and so far it has worked very well for me.

An 8" pot is exactly what I put them in. I let them adjust for a week or so before transplanting and they are doing fine, lots of new growth. I'll transplant again into a large container within a month or two. Thanks for the info. This is the first year that I've had varieties other than my Lavander Lady, which I couldn't kill if I wanted! lol