Can you please put some logs.
Looking at your log, what i can see is that you have made no use of the first proc of MoD. While it is unfortunate that you have procced MoD from your first cast, you should not be delaying AP till 4 stacks, as it is 15 seconds, the ring is 15 seconds so there is no reason to cast slower blasts.
You should AP from the moment your first blast land, and then there are 2 options.
1. Your MoD didn't proc on boss -> Crystal, spam 5-6 blasts till u get AM procs, dump missles.
2. Yoor MoD procced from the first cast, AP, blast boss till 4, crystal, blast on crystal, AM on MoD target.
In both cases, when you open with lust, you have time to spam enough blasts to proc missles that will hit the mark.
Also, trinkets like pof, have an internal cd of maximum of 5 minutes, which means if for some reason you stood in front of boss for 5 mins before the pull, you will have 100% chance to proc it on the first cast if you do crystal on pull.
Here is a good example how you should be doing lust pulls as arcane:
https://www.youtube.com/watch?v=T4bxpyvYZbw