I would first ask, "what process will you primarily be using on the job?" If TIG, then you want to focus on TIG.
Let's say it is TIG ... and you are pretty much designing your own program ... here is what I would do:
Start with SMAW, work up to 3F or 3G configurations, the do the same with GMAW. I would not ignore these because they might come up in the future, and it DOES help your overall skill level. Remember, you skill levels grown like a balloon, not in columns. What I mean is that as you practice GMAW, your skill levels with SMAW gets better, and so on.
I would go to out of position TIG ASAP. Vertical up and don't ignore the HORIZONTAL. Do some OH. Don't ignore the HORIZONTAL. Practice open root V-groove with the TIG 2G and 3G, then when you feel confident with that head to pipe. No matter how good you do with the groove welds, transition to pipe is like throwing a hand grenade into your brain. Go slow at first. Practice movements with the machine off. Do this a lot. Practice movements with the machine off. Do this a lot. Practice movements with the machine off. Do this a lot. Oh ... don't forget to practice movements with the machine off. Do this a lot. You might want to practice your open root with a bit narrow of a root opening to start, then work up to real size.
Hope this is helpful!