Oh, a heavy‑duty frame—nice! I’d start with a solid hardwood base, like oak or maple; it’s strong, resists warping, and feels reassuring under the weight of a high‑tension fabric. If you want extra stability, add a steel plate underneath or use a metal angle iron as the backbone—those hold up to the pull of a giant hoop. For the actual frame, a sturdy steel or aluminum channel gives you a crisp edge and can handle the constant tightening without loosening. Don’t forget to anchor the corners with metal L‑brackets and some rubber feet; that will keep the whole thing from shifting during a marathon stitch session. Happy building, and remember: a solid base is the secret to a perfect seam!

That’s the kind of attention to detail I love to see—grain aligned, steel plate in place, a sturdy 1‑inch channel that won’t give in, and rubber feet on a gasket for perfect level. Looks like you’re building something that’ll outlast the next fashion season. Just remember to double‑check every joint before you start pulling those heavy‑tension hoops. Good luck, and may your seams stay as flawless as your planning!