Mine are just under 6 feet -and using wind on. I spread my arms wide to measure off -(that is just under 6 feet, as I'm under 6 feet tall) then allow a bit more (a foot more) for rigging. Will shorten windon to ensure IGFA legal. I've seen some using even shorter traces with wind ons -which may make storage easier but I like bit of space between lure and swivel on end of my wind on.
I used Shogun 200lb last few years on smaller lures -(purchased from Lauries bulk hank of it). Good trace very supple. But needs replacing after each billfish encounter as soft.
Have some old jinkai in about 120lb for skippie lures and have also used Duel flourocarbon 120lb on skippy tuna lures. Flouro did work pretty well and seemed to get hit a lot more. Worked well but needed right size metal double barrel crimps to get a good connection -flouro is harder to crimp- as harder surface and smoother than nylon. Preference also to use aluminum crimps rather than metal which can damage line/trace where trace enters or leaves a metal crimp.
Problem with heavier flourocarbon would be not supple and may therefore effect action of your lure
I also use a range of heavier trace for my larger lures 300-400lb. Black magic (tough and supple), Penn and Momoi all been good in my experience.
Krow you probably need to find some crimps specifically for 300lb. I think Boone do alloy crimps in 250-300lb and 300 to 350lb size. I'm always buying crimps it would seem and trying get right sizes -possibly downside to using different brands and diameters of trace. The crimps we use for 400lb will slip on 300lb trace and 200 size crimps won't fit 300lb trace, as I've found out when re-rigging odd lure rigged on 300lb and using the small selection of crimps I take out on boat.