Flat or round??

My Schoolhouse Shetland Pullover is progressing nicely. I am now working on the yoke area. This sweater is worked in the round, with steeks and various other interesting techniques, new to me. I am an experienced knitter, I have intarsia, Fair Isle, lace, cables under reasonable control. I have knitted all sorts of things, from big blankets to tiny Christmas ornaments. I love knitting on DPNS. But knitting a large item in the round just isn't my cup of tea. First, I knit with one needle under my arm, which leaves my right hand free to wrap yarn which ever way I need; circular needles are very uncooperative that way, they demand I grip them with both hands and keep them cozy in your lap. They feel insecure in my hands, and make me fumble. I even had a phone conversation about this years ago with Meg Swansen, of all people. She advised me to look for long DPNS. After all, that is what knitters from the Shetland Islands used to use, they even had a knitting belt to secure the back end of the long needle. Let me tell you, long 14" DPNS, are not easy to find. But with luck and perseverance, I got most sizes. Most of them are bamboo ones, made in Hong Kong. Others are metal ones, from Italy. I love them, they are strong, secure, undemanding, efficient in their straightforward way. They are also a bit fresh, and have a habit of letting some stitches slip away. But that does not bother me much. What bothers me is that I do not have a sense of size when knitting in the round. I cannot stretch the fabric flat on my body and decide whether it will fit or not, because a tube does not like to stretch horizontally. A tube on slippery DPNS is definitely not amenable to stretching, unless I was prepared to pick a whole lot of dropped stitches. My current tube is looking lean, too lean. I am beginning to worry. And I have not even tackled the steeking part yet! I am seriously questioning why knitting in the round is so much favored. People even convert flat patterns to round ones. Or knit eminently flat objects, like blankets in the round, then cut them (I do the opposite, ahem). My friend Misa correctly pointed out that colorwork, like Fair-Isle (not Intarsia, definitely not), is much easier in the round, and I agree: that is a definite advantage. Otherwise give me purling and seams anytime, and I'll just be on my way. As for my Blue-on Blue Schoolhouse Shetland Pullover, wish me luck.