I'm really not an expert on mixing fluids lol.
But I wouldn't say 250ml is enough tbh, I probably spill more than that haha. While you're doing it, you might as well change the fluid completely which is about a litre I think. Its obvious to see when the new stuff comes through as it's much lighter.
On the subject of bleeding, make sure you use penetrating fluid on your nipples when you do the unions, don't want them shearing off!
But I wouldn't say 250ml is enough tbh, I probably spill more than that haha. While you're doing it, you might as well change the fluid completely which is about a litre I think. Its obvious to see when the new stuff comes through as it's much lighter.
On the subject of bleeding, make sure you use penetrating fluid on your nipples when you do the unions, don't want them shearing off!