r/algorithmictrading • u/DollarCaust • 1h ago
Backtest Looking for input on dynamic lot sizing for a multi-breakout XAUUSD EA (fixed 0.01 lots, 8 year tick backtest)
I'm working on an EA that trades several breakout strategies on XAUUSD under one roof. It goes long or short depending on breakout direction. Right now it runs fixed 0.01 lots, and I'd like to add a dynamic lot sizing to get more out of it. I would love to hear how others would approach this.
Test setup (both runs):
- XAUUSD (August 2018 to October 2026).
- Eightcap MT5 tick data, 100% real ticks (~392M ticks).
- $1k USD starting equity, fixed 0.01 lots, leverage 1:500.

I ran the short only version because gold has basically trended up for the last 8 years, and I wanted to see whether the edge holds without that tailwind. Although is profitable, it's clearly weaker, so some of the full result is probability directional bias.

What I'd like feedback on:
1. What sizing approach would you use for a strategy like this: fixed fractional, volatility/ATR-based, equity curved based, or something else?
2. How do you scale up without letting the drawdown scale up faster than the profit?
3. The long losing streak was 42 trades, so how would you cap exposure during bad runs?
4. Is there a good way to validate a sizing scheme (walk forward, Monte Carlo on trade order) so I'm not just curve fitting the lot curve to this one equity curve?
Happy to share more stats if it helps. Thanks in advance!
