I am doing some miner repairs, not using teak,
Question #1. Are you doing paneling or solid wood working ? Two different worlds of treatment.
Hunter used only teak oil on paneling and "something" on the solid teak which can be replaced by semi-gloss varnish and look identical. Hunter's choice of finish for solid wood was probably based on a fast drying finish for speed.
For Solid Woodworking. You're going to use a substitute, you'll have to watch the wood you use. Once tried disguising a hidden piece of oak (in a cupboard) as teak. Got the colour right but the wood grain looked terrible destroyed it. Into the fireplace pile. Maybe try birch ? Pre-seal with spray on lacquer (like Krylon) before adding any stain for more even staining. Lots of experimentation required. In the end, it's just a waste of time unless your a professional finisher.
However, you'll save yourself a ton of grief and achieve perfection by using real teak for solid woodwork. Substitution never works. For small jobs the cost is not an issue. Teak is not hard to find in specialized wood shops. Certainly much easier than finding birch. Pick through the pile to find the material that best matches your existing material as the colour of solid teak varies from light straw to dark brown. Finish the wood with #220 paper, and apply three coats semi-gloss varnish.
For Panel Woodworking. You'll have to find a less than full sheet of teak plywood. Can be expensive and rare. Finish ONLY with teak oil.