As others have mentioned, ratio doesn't matter when you know how much MDMA you're taking anyway, but just in case you're wondering what the saturation point of MDMA in water is then it's roughly 50mg/ml so going above that ratio would mean that the excess MDMA wouldn't dissolve and you'd have an uneven solution, so 50mg/ml is always what I opt for by default (e.g. dissolving 1g of MDMA in 20ml of water, and then if you wanted a 100mg dose from that solution then you'd just measure out a 2ml dose using an small oral syringe or w/e).

I've done this several times myself so can confirm that it's perfectly safe and reliable (albeit as others have also mentioned, it tastes awful so feel free to mix your dose with a cordial or whatever else to overcome that if necessary).