Yes, use them together, it just won't touch the rakers as doing them with the husky guide will take them down a touch lower. Now one caveat is that the husky raker guide doesn't work with all chains.Not quite sure I understand. Are you saying use the above tool and the Pferd 2 in one together? I am having a hard time visualizing how that would work. BTW, no Husky dealers here, except TSC and maybe Lowe's. Not sure if they have one. They don't sell any pro-grade saws. But, to answer your question on how the Pferd system can still result in a curved cut, the answer is simple. I tend to do a better job of applying pressure on the right hand cutters than the left. That would be a problem with any hand filing system that does not have an adjustable file stop, such as the Granberg file-n-joint does. I used the Granberg before and it does a great job, but it took maybe 15-20 minutes to set it up and get the job done. Freehand filing was faster but I had to still file the rakers separately. That made it about a 10 minute job. I have it down to 5 or less with the Pferd system. But proper use of the Pferd system, just as any other hand filing method, requires some skill, and I am endeavoring to improve mine.
You could order one online, but you shouldn't pay more than like $12-15, I've seen places charging 30 or more.
The point about it cutting curved was that the reason it's cutting like that is not because the cutters are a different length, but rather because one side needs the rakers lower than the other because the cutters are shorter on that side. With the 2 in one you are removing a fixed/set amount off the raker, this not removing enough on the lower cutter to take a similar chip to the cutter that's taller. That's why when you send the chains out and the cutters come back an equal length they cut fine even when you use the 2-1 to sharpen them, at least until the cutters get filed different lengths.