I would commission or make a painting! You will never get that exact look from a photograph.
The most important aspect will be your model, their hair, clothing, props, and how you direct them. After that, look again closely at the pix and analyze the light that Vargas painted. Analyze the quality of light, the supposed location of the source, the contrast, the saturation, the color palette, the skin tones, the backgrounds, etc. If you can break it down technically, you stand a better chance of being able to do this photographically...and you will also see that there was a lot of variation painting to painting, and not just one "Varga Girl Look"!
I worked for an estate sales company that recently had about 100 calendars from local industrial companies that featured similar style oil and watercolor paintings. We also had in a bunch of promo material from The Zieglield Follies, including several Vargas prints, and some Petty prints and an Elvgren calendar from a local industrial plant of some kind. They are incredibly striking in person, even as relatively low quality lithographic prints. They were all different, but some main features of the style were low saturation, pastel color palette was common, soft line work (IMO the single most distinguishing characteristic, and also the hardest to do with w photograph), light skin tones, usually empty and usually light colored backgrounds...not to mention EXTREME photorealism on a majority of the work (though Vargas' and Petty's were some of the least photorealistic of the 100+ prints that I saw, with the most unrealistic - read unnatural and sometimes impossible - lighting, with unbelievable core transitions to the shadows; quite cartoony compared to some other artists who painted similar subject matter). I thought that the non-Vargas/Petty calendars were photos that had been airbrushed and painted over at first. I think it is likely that these extremely smooth and realistic ones were originally oils and not watercolors. The main trick for you, IMO, is getting that incredibly unique and subtle combination halfway between photorealism AND soft linework..........GOOD LUCK! *Learn to paint* is my honest-to-god suggestion.
Then, after all that hassle, ask yourself WHY? Why mimic another artist so directly?
