Now I know why it costs so much to have these made. Being a novice at this, I went to the library and checked out several books on making slipcovers. Read them thoroughly. Only one of the three actually gave explicit instructions. The other two pretty much left out the steps getting from "Buy your fabric" to "Put it on the chair."
I started out by making a muslin cover so I could figure out where the difficult parts would be and learn how to handle them. Well, I figured out where the difficult parts would be but didn't solve how to handle them, at least not very well. When I got the slipcover fabric I bravely set off. The book said to make the seat cushions first, just for a psychological benefit. So I did. But the first cushion turned out way too big, and then I decided I should buy new cushions since why go to all this effort and use old cushions? I'll save the cushion cover til later.
Anyhow, after a lot of bad language, ripping out, frustration, and hair pulling, I finished one slipcover. I took it to chair #2 to put it on. I had used chair #1 as my model. That's when I discovered that the chairs were fraternal twins, and not identical twins. More bad language, but no more ripping out. On to the second slipcover. Which wasn't any easier, and even developed its own new problems.
But finally they're done. They're not perfect but they are pretty good. Slipcovers can't fit as well as upholstery, so I can live with the wrinkles. They look much better than they used to.
After I was about 75% finished with the second slipcover I discovered a website of a guy who sells step-by-step instructions of how to make slipcovers, geared towards the beginner. I was particularly interested in the "tips for first-timers". He suggested to not try to tackle a chair with an attached back cushion, wings, or curved arms. Check, check, and check, my chairs have all three. Probably better I didn't know that up front.
And here is Rosie, now 8 months old. She supervised from her comfortable perch, or helped by chewing the tape measure, pulling out pins, and knocking stuff off the table.
And now gotta get back to doing some art. The snow has melted and Spring is starting. Hooray!