In reply to your question, Mark, oils can be thinned quite a bit using either a medium, mineral spirits or turpentine. I usually thin oils to about the consistency of skimmed milk. Sometimes it takes two or three coats to get the desired coverage, but you have better control and more pleasing results. Nothing worse than a thick coat of paint on a figure. FWIW, this was the hardest thing for me to learn as an oils painter. I know there is a technique in which you put the oil on without thinning it (straight from the tube) and then brush off the excess. If you're used to working that way, I guess it's worth a try. I could never make it work. The good news is that if your paint is too thin, you can always put on another coat. If its too thick, - not much you can do. So don't be afraid of thinning it out.
Welcome to the forum and good luck in your painting.