I am running a 5.10 D606 Dunlop on Lil Kanes ride.I put 4 shim washers between the pipe mount and the pipe to move it out a little away from the tire.Chain adjuster is about 3/4 way to rear.Shock spring preload is ran way down to reduce shock bottoming.
I know I had 606's on my 250 and I'm pretty sure that they are the same with as HC's.
I had a 1" spacer between the subframe and the mount and they would kiss the muffler when it hit hard. I think they actually cracked the exhaust, but I'm not sure about that.
The other thing you really need to watch is the radiused area at the front of the swing arm. They will get very close even with a used chain and sprockets. I noticed HC said his were 3/4 out and thats about where mine were when I tore down. New chain, fresh sprockets, might not have allowed the PO to put these on.
Just because its been done, doesn't mean it'll work everytime.
I saw someone alot smarter than me say "follow the manual and if you don't have one, get one".
Pretty good advice since that will give you a basis to start from. Explore on your own nickle from there.