David, I'm not experienced in the field like these guys are but have immersed myself into learning all I can. A bad habit I have when I really get into something.
What I've learned so far. Lots of folks looking for welders who can tig the root, some I have heard tig the hot or tig all the way out. Tig stainless, aluminum bonus, bonus. I've also seen lots of jobs out there in the shipyards, usually at this site
http://www.roadtechs.com/ Most of those are jobs doing FCAW with ceramic backing, something they ask you if you have experience with. Me, I ran mig the other night at school, 28V's and I stunk up the place pretty bad. Been a long time since I've run the big wire/heat....you know what, I could'nt give a rats behind about the mig anymore.
Talking with these guys like I have for the last 6-8 months, I know I don't wanna do the shipyard thing, sounds like alot of trigger time. Get to know your uphill/downhill pipe. I'm actually doing downhill myself trying to get gas certs. I'm with you, I dig welding the pipe. Another place that has been mentioned on here for jobs was
http://www.rigzone.com/jobs/ I've seen some structural jobs there mostly. As far as the shipyard thing goes I know I've seen pipewelder jobs on there, most are 5 years plus experience and shipyard experience. Don't know how to go about getting your foot in the door to get experience though.
Like these guys said though, the more you know the better off you'll be. As far as your 3/8" plate tests if your doing 1" then that'll qualify you for unlimited down to 1/8" . I did my overhead 1", cost me the same for the test as 3/8" except I got more out of it. As far as I learned, my opinion is that the smaller stuff lets you practice your cap pass and get it good. The thicker lets you practice stringers all the way out, what I learned is you have to pay attention to how you lay your stringers in so when you get to the top your not piled up on one end and barely over even on the other, being consistant.
Like I said, not nearly as experienced as these guys but this is just what I know now. Hope something I've said will help out, keep poundin' that rod!!