I agree that I said that cashing out 10% every time the BTC price doubles is a fairly conservative approach to price-based sustainable withdrawal.
Also, I am pretty sure that I said that selling 10% every time that the BTC price doubles is one of the possible portfolio management (and sustainable withdraw) methods that becomes available after reaching overaccumulation status. Guys will sometimes start to employ methods of selling BTC prior to their having had reached overaccumulation status, and to the extent that my opinion matters, I do not agree with selling BTC prior to reaching overaccumulation status unless you are engaging in spend and replace or you have some kind of an emergency or you are cashing out due to age and/or health concerns.
It is a very good sustainable withdrawal while almost giving good chance of buying back and having nearly same or even more amount of bitcoin later when price has pull backs, corrections, drawdowns or crashes.
When Bitcoin price doubles, your initial capital can be doubled too but it's very rough assumption because it depends on your entries and prices of accumulating bitcoin before. If DCA strategy was applied well, your average entry price would be not too far from a half of Bitcoin price (let's say its doubling price at a time of your taking profit action), so withdraw 10% of your investment capital is good.
With remaining bitcoin and capital, you can reaccumulate bitcoin in next dips without big decrease in your total bitcoin amount.