I took a look at the service manual on page 5-6
On step 6, check horizontal gain.
I connected a voltmeter to E Sense and Base and got -95mV at 0.0 on the offset multi
When I turned the offset multi so I got -595mV it seems the manual indicates the spot is supposed to move somewhat but I didn't notice any movement of the spot, I believe this is a good indication?
I should note I did not see no spot but a flickering line 2 divisions long, I thought I could tell if there is a deviation by looking at the ends of the line and noting the new relative location, I noted no change of position.