มีใครประสบปัญหาเรื่องการกำหนดขนาด Position ในหุ้นที่มั่นใจมากๆ บ้างไหม?

Totally get this. I've found that having a pre-defined maximum for any single trade, regardless of conviction, helps. It's like setting a speed limit for yourself even when the road looks clear.

That's a classic trap. If you 'know' it's a winner, you're already in trouble. The market doesn't care about your conviction; stick to your predefined risk parameters regardless of how good a trade feels.