Welcome and here are my answers, others can add or correct
push button leg mounts on the floor tom, that was rare
Not necessarily rare, but to find all of the push buttons in place and good working order is getting harder and harder.
Also what about straight legs on the floor tom
Does not affect value.
and straight slugs on the base drum vs. the curved type, are those common or more rare
Do you mean drum lugs? Slugs are those sticky creatures and if you have them on your drum we are in trouble!! I had to do it!
You should clarify this a little
What is the strainer on the snare
This is the mechanism that raises and lowers the snares (wire) on the bottom of the drum
Is it the wires that run across the hitting surface on one side
Nope, the top or the batter side is the side that is hit and the other side is where the snares (wires) come in contact with the snare side head. People do call them different things, but batter and snare side work for me.
why is it called a "strainer".
Good question and the dictionary has this a stretcher or tightener.
And why is the lever called a "clam shell"?
The lever on the strainer is called the strainer arm and it controls the snare wires. The clam shell is the type of strainer your drum has.
As you can tell I am pretty ignorant when it comes to drum lingo!
Nope, we do not like to use the word ignorant for people that take the time to do the research and learn about what they are selling.
So your Slingerland Drum set has a snare drum with a clam shell strainer. The strainer arm is what controls the strainer to make the snare wires go up and down on the snare side head of the drum. You play the top of the drum which is called the batter side.
This does not even cover the "Butt" side. Ahh, yes we call the thing opposite of the strainer the butt side and that is the other side that the snare wires are connected too!!
David