I have 2 1950 "Porthole" sets in my collection. They are not a quick fix kind of set, Numerous problems, tons of caps to replace, etc.. It took me about 2 years to work out all the problems and get 2 good working sets. I eventually gave up on the 12UP4 crt's and use 12LP4's in both sets now. I've always had the best luck with the late 40's Admiral sets. Here's a link to my youtube videos on the portholes:
http://www.youtube.com/watch?v=ATVpoVVuTzs
http://www.youtube.com/watch?v=Cgp4EtkGSFg
Jim