Every version of this strategy runs on one behavior: money goes out of the hub, and money comes back to the hub on a schedule you set. The bank is not going to remind you. That's the feature people like and it's the exact place the whole thing falls apart.
A line of credit will accept the minimum interest payment indefinitely. You can carry $30,000 on it for six years, make every required payment, never miss anything, and still owe $30,000. The account looks healthy. Your credit report looks fine. And the strategy has stopped working, because a hub with a permanent balance on it isn't a hub anymore. It's just a second mortgage with a variable rate.
So put the payback on the calendar the same day you take the draw. Decide the amount and the end date before the money moves, then set the transfer to run automatically. If you chunked $20,000 and your real monthly surplus is $1,200, that's a seventeen-month payback and you should be able to name the month it ends.
Two rules keep this honest. Don't take the next draw until the current one is retired, no matter how good the next opportunity looks. And when income jumps, the payback gets the raise before anything else does. Those two together are most of the difference between people who finish this and people who talk about it for four years.
Track it somewhere you'll actually see. A single line in a spreadsheet with the draw date, the amount, and the scheduled payoff date is enough. What matters is that the number is visible when you're deciding whether to draw again.
If your hub is a policy rather than a line, the discipline is identical and the consequence of skipping it is sharper, because an unpaid policy loan compounds against your cash value and your death benefit. That's covered at nobody bills you for a policy loan, set a schedule anyway.
Before your next draw, figure out what the real surplus is, because the payback schedule is only as honest as that number. Here's how to find it.