I think you have exactly the same car as me. 91 1.8 190e manual?
I've been having an intermittent hesitation problem myself. Replaced fuel filter and spark leads and its still there. Only happens every hour of so of driving.
I have decided that it might be either dirt or water in the fuel tank or a defective fuel pump pressure reg or relay.
Anyway back to your car!
The ezl resistor has six positions which I beleive go something like
6 lowest advance unleaded petrol
3 highest advance unleaded petrol (position s I think, I've not got a picture handy and its dark outside)
2 leaded fuel low advance
1 leaded fuel high advance
What I dont know if is 2 and 1 give more advance than 3. In this country leaded had a higher octane than unleaded.
I'm waiting till I next visit my parents as my dad has a timing gun so I can check for sure.
I've tried the positions 3,2 and 1 and I have left it on 1 as there seemed to be a bit more torque at low revs.
Position 3 or S is the position most people recommend.