The teaching I received (on an actual classroom course!) in stock trading was to maintain 5 open positions, each comprising 20% of your capital, each having a stop of -10% of the entry price. This means that even if fully committed, your account capital is damaged only by 2% if one of your stocks hits its stop-loss. The stop is trailed at -10%.
Bitter experience however has taught me that stocks tend to move together when a market correction event occurs, and this will probably hit more than one stop simultaneously. Plan for if it hits all of them.
Therefore, I would trickle money in at first and ride a winner until it shows a trailing stop which is now break-even and so cannot damage your account capital, then add the second stock. And so on until its possible to add a third.
A feature with this approach is that it can take a long time until you are fully invested. That can be ether good or bad of course. Secondly, if you only ever exit a winner when a trailed stop is hit, you must always be handing back a large chunk of unrealised gains.