I think the number 108 is not bad, but it is not necessarily the best though. And you should evaluate depending on the kind of magic work you have to do.
If you have to do magical work to get rid of negative influences it may be okay. On the other hand, if you have to do magical work related to, for example, boosting a chakra or healing/vitality, 111 or 216 are definitely more suitable, as they are solar numbers.