TRISTAN - I'd double check your first driveshaft, it might be short on the engine end also, or maybe both ends, depends on how you hold it in place I guess.
If you talked to Julian and he said they sent you a NF driveshaft then that's what you got I'm sure.
I don't think you need a 6-pin driver, and I'd stay away from an aluminum surfaced clutch, they're an "On-Off" switch, not what you want for beating around in the woods. The Q/L clutch drivers were never really strong, they had to bend to allow the engine to rock around on those rubber mounts and IH chose to do that flexing with the clutch driver. I'd get a new stock driver since they hold up 20 or so years or ask Julian what he'd suggest.
I think I commented before that I went where you're heading with your CC in the clutch department and I went back closer to stock after 150 operating hours in 4-5 yrs and one totally trashed throw-out bearing. Even a tired stock clutch puts more power to the wheels than the tires can ever hope to put to the ground on muddy grassy conditions. I think most pullers solid mount their engines and use a more rigid driver from a NF CC.