I started with Stock SH3, did the academy and he "happy times and gibraltar" single missions - - never made it through the straits. Then i began a career in 39 at 60% realism, and upgraded the realism after each patrol. I am in early 1941 at 80+% realism. In April I downleaded GWX and began a career in 39, 80+% realism amd am now completing my 3rd partol. I may go 100% at some time, but I need to get a lot better before I do.
Hope this helps -- good luck on your careers