Cam duration isnt all that big so I would expect 8-10 inches of vacuum. Your new idle of 1600-1800 can be a couple things.

First off a few things will make the idle sit high. Additional air as we have discussed and Timing.

What you can try is to set the idle bins of the car at 17*. Now just doing that isnt going to change a thing becuase the idle is stuck at 1600 RPM and 8 inches of vacuum. So to pull it down to where it should be (1000RPM) you can use the clutch with the parking brake on.

Make sure you have enough fuel at idle, not enough fuel will cuase it to fall off as well.

If the car will idle when you pull it down with the clutch then your hanging up due to your timing advance off IDLE.

The tiny leaks you have most likely are not the cause. Your tuning is which means its fixable.

Rules to tune with:

Retarded timing will cause the idle to drop
Advanced timing will cause idle to raise
Open plates will cause idle to raise and Vice Versa
More fuel will cause idle increase and Vice Versa
Advancing the cams will give you more low end at the cost of top end
Retarding the cams will give you more top end at the cost of low end

Do not expect those cams to idle like stock, they wont. Dont expect idle vacuum either. Once you get your idle down to 1000 then start tuning the mixture to the vacuum reading. Lean out the Idle fuel to raise the vacuum. When the vacuum stops raising go 1 or 2 points richer on the fuel mixture.

Advancing the timing will also increase vacuum. But as I have stated you are going to push the idle up so you counter that with closing the throttle plates a tiny bit. You dont want the plates open too much and you dont want them closed so much that your timing is advanced to the point the car doesnt want to start. Timing advanced too much will cause the engine to fight itself starting.

This info should be enough to get you on the right track, remember to work methodically and be patient. Rome wasnt built in a day.

Terry