I've been running Noodler's HoD in my Vac 700, and love the combination, but I've noticed some leaking around the section ring. I've pulled the nib unit, and the O ring is fully seated, and the nib unit is properly tight. There is no looseness, and gently trying to tighten the nib unit further shows it's fully down.
It currently is using a Goulet 1.1mm stub, but the problem has been present since before with the stock nib, and has not worsened. The feed holder tube did break a while back, but has been replaced.
What do I do to remedy this? Should I pack the ring with silicone? Ask TWSBI for a replacement nib unit? Replace the O ring?