My 301 sews fine with Schmertz needles, but prefers Singer for FMQ. Weird, but whatever. My Elna only likes Schmertz. I've never tried the self threading, but you aren't going to hurt the machine by trying them. All size 15 needles are the same length. I found packs of 11 Singer needles for $1.99 at my LQS. I bought all they had and AnnieRose sews just fine.