Actually there is someone on e bay selling just the needles. Dont know if they match DJ or GYTR. Also I think you can go to ALBA's website and you can buy individual needles but you need to know the number on the needle that you want.
If you get them let us know if they have 5 or 6 clip positions and the number on the needle.
The other part of getting "aftermarket" needles is getting the correct lenght, taper, and diameter. That is why I always recomend dynojet or gytr (if you want to stick with mikuni mains). When you buy these brands your paying for the r&d time they put in to develop and test the needles. Vs. Paying some one like vito's or alba who matched up a needle that is kind of close. 90% of riding is done between 1/4 to 3/4 throttle, right where the needle controls fuel, so I wouldn't sell it short.
GYTR kits include 140, 145, 150, 155, 160, & if I remember right a 165 main as well. It also has 2 # 25 pilot's a set of GYTR needle's & a GYTR decal. Ow ya & a page on jetting from GYTR.. I personally thing DJ needle's are better depending on your build.
FYI, the GYTR needle's have 5 adjustments & the DJ needles have 6.
Here is some good info on Jetting. It is geared twards 2 strokes, and Keihin PWK, PWM, PE, PJ carbs, but the carburetor functions are pretty much the same, other than 4 strokes haveing fuel screws, and 2 stroke carbs haveing air screws.