Tach for tuneups?

There may be something. Might have to cross post in Shop & tools.
For anything around idle and even fast idle, I prefer the tune up one like your tach/dwell.
For checking timing at higher rpms, I used to use the one on top of the dash.'
Yea take a timing reading and then look inside. Then turn the idle stop screw a little more - 'till timing advanced a couple degrees or rpm went up 500 rpm or whatever internval seemed enough.
Now I have automotive multimeter with tach function. Its a little more convenient.
Multi-spark can't use all those. Need to use the tach output of the MSD box...