Manicmike and Mrs.SewandSew, thank you for your helpful responses! The UK site does clarify about the spring, so that is very helpful. It does recommend using 3 of the 5 available tension holes, but when I did that the tension seemed VERY resistant. I've backed it off of one hole and will see how it works once it's installed and the needle is set.
Mmike, I found resources for both needles and *new*ly machined bobbins which seem to fit perfectly. I have a good number of needles, but I think only size 14s are available. I haven't gone in yet to try installing the shuttle, but will report back tomorrow! Let me know if anyone would like info on bobbins and needles... and thank you again (so much) for your help!
Ellpea aka Pamela