I don't know, not quite touching the swing arm without rider sounds a little tight. But I do tend to like mine on the looser side.
I know this might sound like an elementary question, but you did assure of rear and front sprocket alignment. Those factory marks are not quite dead on, I don't like relying on them.
The front sprocket nut, Front Swingarm nut, and the rear axle nut should all be in perfect horizontal alignment when adjust the chain. This point is the Longest point the chain will have to stretch, anything else up or down will be shorter. I usually like at least an inch of lower chain movement when these three points line up.
Oh I do know, that when I ordered a 16 tooth front sprocket, the forgot to mention the spacer washer needed to go to the inside to shim the sprocket out enough. Just another thought if yours came with one. Some people like me, ahem, thought they went to the outside of the sprocket.
I know, probably not much help, but I am trying.