You can trade any lot size you see fit, but mind that significant size leads to too large risk/exposure.
It is best practice is to base your risk per trade on the equity allowance you have for the day.
Here’s an example
Imagine you are risking 1% per trade of the balance while being close to the day’s equity limit.
If the trade goes against you and takes you over the equity limit, then it’s instant disqualification.
A much better way would be to risk only a portion of the free equity you have left on a given day.
By doing this, your risk is reduced each time a trade goes against you and keeps you on the right side of the equity limit.
Our full-time traders are required never to risk more than 10% of their daily equity limit, and we suggest you also follow this method.
This would allow you to have ten losing trades in a row and not be disqualified from trading.
This is, of course, entirely your choice but has proven very effective.
It’s especially useful after you suffer a significant drawdown on a live account, as it makes it impossible to breach the max drawdown rule.
For example, you have calculated rest equity that allows you to lose 2400 USD, which would result in the next trade to carry a 240$ risk. If this trade would have lost, you would still have an equity limit of 2160$ left. The following trade would then risk 216$ if that trade wins with a 1:3 risk-reward that would push your free equity up to 2808$, and you could risk on the next trade 280$.
As you can see, by this way of trading, breaking the Drawdown rules is almost impossible.