Hi Bilben! We corresponded last year just after I bought my HZL-DX7, which is very similar to your F600. I totally agree about the 8.5" harp. I've used my DX7 to do FMQ on smaller projects, and it works really well. It's not "finicky" about thread, and no tension problems.
For larger projects, up to about 70-75 inches wide, I have a Juki TL2010Q. The harp is 9 in. wide x 6 in. high. It's a nice square harp, not the same shape as the DX7 or the F600.
That being said, I'd love a machine with a much wider harp, but I would also look at the height of the harp. So far, the machines I like are way above my budget.
Do you have a Pfaff dealer locally? I'm guessing that you don't have that many dealers in Whitehorse?
I hope you find the right machine for you. Please keep us posted.