It is a lot!! I was surprised myself. And also surprised how little 50ml of water is. It's going to be hard to drink
But don't worry about it dissolving - it's not the same as table salt.
50ml is so little, right?! i'm going for 75ml myself, maybe it'll be a bit more bearable. but then again, i've drunk and kept down worse tasting things in my short but miserable lifetime.
i haven't tried dissolving the table salt myself, but 84.8 g/100 mL at 25 °C compared to table salt at 357 mg/mL with the same temperature (which, if my meagre math skills haven't failed me, is 35.7 g /100 mL) is definitely a significant difference and something to keep in mind when experimenting with good ol NaCl before drinking SN. that's not accounting for the additives like iodine either; though they probably don't make much of a difference.
to answer OP: i don't think warm water is a good idea. salt water flushes are usually done with warm water and they can lead to nausea and vomiting... but again, SN is a different substance, so please correct me if i'm wrong.