Let's get it from an expert. This is the information I was supplied when I asked a well know gunsmith the very same question. I had over 25,000 rounds through my DB81 combo before I sold it and the lever was still well to the right........ Dan Thome (Trap2)
Dan,
I suggest letting the top lever trip and close on it's own. Easing it down, I would think, would be like closing the bolt on a bolt action rifle just half way. It will not lock tight.
One other thing. On occassion, when I rebuild or replace a locking bolt, the fit becomes "too perfect". You would think the the closer the bolt mates with the lugs on the bbl...the better. But what can happens is the bolt gets just too damn sticky on the lugs, making it difficult to push the top lever. I think this is why Giacomo recommends to ease the top lever. I've heard a few shooters that have complained that the new bolt that Giacomo just installed, has now caused a problem opening the gun. Easing the top lever allows the gun not to lock too tight.
Like I've said, I do run into it once in awhile. I usually make sure the lugs are at eight degrees. I now regrind the bolt at 8-1/2 degrees. At degrees, I will see a 50/50 chance the bolt will be sticky. You DO want a little stick, this is what keeps it locked during the shot, but not so much that it takes all your might to push on it. The 8-1/2 cuts the extreme stickiness to less than 10%. After about a thousand shots, the two mating surfaces find their happy medium, anf the gun is good to go for the next 30-40 thousand rounds.
Just my take on it,
Doug