whatever size you're going to buy check with ebay, cheaper than any place else...***2 all!!
LUCY, I TOO OWN A JANOME 350E. I USE SIZE 11 WHEN I AM WORKING ON FSL AND USUALLY A 14 FOR DESIGNS WITH LOTS OF DENSITY. I BUY MY NEEDLES FROM ALLSTITCH.COM. SEE THE LINK BELOW.
LUCY I BUY NEEDLES IN PACKETS OF 100 FROM EBAY BUT I AM A UK CUTIE. THERE WILL BE SOME SIMILAR SELLER IN THE USA FOR YOU TO BUY FROM. I ALSO GET THE 90 SIZE