I play a lot of ffrk and mytrhil has always been an issue but for right now I'm waiting for the Golbez event so I'm not spending a lot. What has worked for me all this time is not to spend mytrhil on events of only one ff I mean I only use mytrhil when there are hybrid events of more than one ff like the coliseum events or the likes and this works because I get relics for different ff's that can be used in the future.
I'm really behind the coliseum and the ffx event but I think that between today and tomorrow I will at least do u+ and the current coliseum event, but I'm really afraid to do the u++.
Also, don't you use hit and run for the u++. It helped me a lot last event.
Finally, since multiplayer is near lets add each other. My code is oMPi an my username is the same Gr8Pulse