I just opened a position at 0.39c on NO, and now the price has already risen to 0.69c. I decided to reduce 50% of the position here to fully recover the cost basis. This way, I can have a zero-cost position to hold, and subsequent rises or falls won't affect the principal safety.

This approach is actually quite common—when a position has already yielded good profits, lock in the principal first, and the remaining position can be more confidently pursued for further upside. There's no need to worry that a pullback will wipe out all gains, while also preserving the opportunity to continue participating in the market. Now, since this price level still has room to rise, let the remaining 50% follow the market.