Just to suppliment the good advice of GRoberts, Know that E71T-11 (Hobart Fabshield 26 or Lincoln NR-211MP ) gasless filler does not really love multipass welding, but it can be done, in order to do it with maximum performance take great care to remove the slag from the toes of the weld after every pass. With your setup and thicknesses 1/4 inch and over, a little preheat with your Oxy-fuel rig might be a good thing.
http://www.hobartbrothers.com/pdf/Fabshield21B.pdf
http://www.lincolnelectric.com/knowledge/articles/content/20faq.asp#3
Or if you just happen to have a big wad of cash burning a whole in your pocket try http://www.aws.org/pr/august11-98.html Thats a bargain at $7.50 U.S. per page eh?
>snort<