Well, it may please some of you to know that I ended up getting SH3 instead of 4. I've installed GWX 1.03 and am having a blast. I'm now on my third patrol and encountered the HMS hood! See the results below:
Admittly I did not use manual targetting, but otherwise full realism. Sadly, its 8 destroyer escorts saw me and sent me to the bottom of the channel Das Boot style. I've gotten the flooding under control but the destroyers are still after me....