Hi there! I can’t probably tell what DD/Gains ratio shall be considered ‘good’ because I’m unaware of your strategy. But the only thing I can tell is that - It’s a good performance as long as you are happy with the profits. Word of advice - don’t become greedy. Focus on trading psychology more as you already have a strong strategy. Now your main enemy is your own mindset.
Using stop loss is necessary not only for risk management but also for money management. Aim at not risking more than 2% per trade even if you think you have enough capital. Secondly, use a lot size trading calculator for help. Moreover,lot sizes do not depend on whether you are using stop loss or not. So it wouldn’t affect me.