Mousse and gel are COMPLETELY different products, darling, with a completely different level of hold, and completely different finishes to achieve completely different results. So, bear with me, and I'll give you the lowdown, since I have used both, BWAHAHAHA!
Okay, to start off with, mousse is a light foam, which can give your hair bounce, volume and such. Its good for any hair that needs lift, and has a bit of hold, but should be scrunched throughout the hair, and used quite sparingly, as too much can leave your hair slicked together in sticky, crunchy, stringy strands. Make sure you use heat with this one, as using it dry can achieve the same, stringy effect.
Gel, which is a thick goop with a high water content [which allows it to be reactivated by water], has a HUGE amount of hold. Its a sticky goop, good for spikes, defining ends, contouring your hair shape, taming flyaways, and is better for thick hair, as thin hair can be weighed down and gooped up by the gel. Its definitely best for shorter styles, and is fairly tricky to use on curly hair [and will require practice], as it can be devastating to a style if used in excess.
There are certain blow drying products specifically for curls that may be even more suitable. Look for curl-defining products that add shine, body and bounce. Good luck!