Hello Evelin,
If you want to ensure that the sunflower lecithin is properly dispersed, reduce the emulsification time, mix the melted fat part and add the sunflower lecithin and add this mixture to the aqueous phase and emulsify.
But actually we weigh all the ingredients at the same time and we have not had any problems, it just takes longer to disperse so we have to emulsify longer.
I hope I have helped you.
Happy day!