Split the difference from where it was, to where it is, and you should be dead on. Also, since you will have the carb off, As Mike has suggested spray carb cleaner (use the want) through the air vents and make sure you observe a reasonable flow out the other side. If it backs up and sprays you in the face, and dribbles out the other side, there is an obstruction.

Ok so 1 vote for raise the fuel level and 1 vote (with pic!) for leave it as is.

If we assume the fuel level in the bowl is good, any thoughts on what may be causing the momentary stalls?  It's real similar to a prior post on here where a guy was fighting the same issue and it turned out to be a piece of paper towel that the main would randomly suck up and cause a blockage.  It feels like that same issue.  I'll double check the bowl for debris but I'm positive it was clean when I reassembled this past weekend.

Also, right now I have a #145 main jet which is the stock size according to the specs post (and the Clymer manual I believe).  I wouldn't think that would be the issue.

On the idling front, it doesn't seem like any of my tinkering has made a difference.  The best idle is with the idle/mix turned all the way in and the knurled knob screwed down as far as it will go (I think you can actually see that in my fuel level pic).  Even then it's not great.  

Tonight I'll get a pic of the idle/mix screw.  I noticed yesterday that the head looks bigger than my last savage and larger than the pics I've seen here.  Maybe it's not the right screw and was replaced by the prior owner (or maybe I'm grasping at straws .  I'll pull it out (with out loosing and of the other pieces in there) and post a pic.  The idle issue may be something crazy like that.  If that's not the culprit than I'll pull the carb and triple check all the passageways with carb cleaner.

So, to summarize, no change to idle behavior, and now the bike momentarily stalls at speed.  I'll check for debris in the bowl and get a pic of the idle/mix screw.  If no debris found, maybe I will raise the float just a hair.  That's the only thing I can think of at this point.

Yep the choke was all the way in.  Here's a closeup of the choke plunger when the carb was on the bench and I'll post the close up of the cavity it seats into.

B-Will you certainly have a bizarre problem.  That enrichment plunger looks like it hasn't moved in years.  What do you think all those little balls of crud are (the stuff on the proboscis)?  Corrosion?

Based on your description, the engine seems to be getting too much fuel. You say it runs better when the mixture screw is turned all the way in, but it's also doin stuff that indicates a big air leak or the enricher is stuck open.  It sounds crazy. 

Can you take the carb off, disassemble it, and take a full set of pictures so we can see all of the parts?

I didn't have time to pull the carb tonight, but I did have time to pull the idle adjust screw.  I think this may be one of the issues.  When I look this part up on Partzilla, it's definitely different.  Some other observations:

- As the screw sits in the cavity, it sticks out way more than my last savage as well as other pics I've seen on this site.  With this screw, there's not even room for the brass factory plug to even have been there in the first place.  Looking at the screw close up, it's clear why that would be.
- O-ring is obviously not serviceable anymore.  Even with the correct screw, it probably would never have seated correctly.
- spring and washer look good

A few pics to follow:

The other components of the idle screw assembly.  Note the o-ring is trashed.  When I was removing it, it was crumpled.

I think the reason it was only running when the idle screw was in all the way, was because it's wasn't in all the way.  The combination of an incorrect screw and/or the o-ring being deformed in the cavity prevented the screw from being fully turned in.  I was being pretty gentle, so I wouldn't have known if I was compressing a jacked washer vs. fully seated screw (just a guess).

The mixture screw you have is not the standard one....perhaps it is not seating properly and controlling the mixture as it should.