My best tip for you making the MAM is adding the scoop of MAM to your sachet(whichever flavour you fancy,i love strawberry) and giving it a good mix around with a spoon before your add it to the water,this way the MAM is well and truly blended into the sachet.Then add it to the water and i use a blender for about one and a half minutes so i know it will be well and truly mixed up.
I have to say i use a little more than 150mls of water as i find it a little to thick for my taste,i use around 200mls,but it really depends on your taste i suppose.It still sets well for me i just have to leave it a little longer in the fridge.
Hope this helps a little