I haven't tested mine yet, but have done a quick and dirty assessment by putting a schmetz #18, an HLx5 #18 and a 206x13 #16 side by side.
Sad to say, the organ HLX5 is about the same size as the Schmetz. They are shorter to the tip, but it's in thousands of an inch shorter.
So at this time I have to say there is no difference.
I'll ge tthe vernier out and put some numbers on these difference, but I don't think it's going to work.
Now, they will work in my machine since the schmetz 15x1 needles do (again, not recommended that everyone with a 319 go out and start using 15x1's). The organ needles are noticeably more robust than the schemtz. I'll be swapping to the Organ needles for that reason alone....