Dont use a shock collar, unless you 100% clear in your mind what you want to achieve ,when to use it and where,,the collar works best if its used just to change his frame of mind in situations,,
what ever you achieve with it ,you wont achieve any sort of understanding between him and you,and that is where i would start from,
the first thing i would do is get a tug item to play with the mutt with, 1, it brings him into close proximity to you when in drive ,something he dont seem to be able to bear up till now,
2,it gives you a handle on him, you will always get the attention of a dog mad for