I've taken the liberty to compile existing advance curves from different sources and plot them on the same graph. I'm obliged to Ludwig, who supplied the TriSpark curve and much private information, and Dave Comeau, who posted the AAU and Boyer curves on his website. 1. The AAU. The AAU curve is the gold standard for the Commando. Unfortunately, as data provided to me by Ludwig has shown, the AAU is unstable from unit-to-unit, with a low rpm (below 2000) variation of +/- 6 degrees. Dave Comeau comments in his website analysis that lubricating his AAU caused an offset of 3 degrees in the advance curve. On average, the unit gives a great curve; in practice, not so much. The unit provides low advance and start-up and tick-over (2 degrees), resulting in no kick-back and a powerfull start and idle. It is all in at 28 degrees at 3000 rpm. 2. The Boyer As this curve is two decades old, it clearly applies only to the earliest analog Boyer units. The unit provides a very large advance (12 degrees) at start-up, likely the source of its propensity to kick-back. Advance increases to 16 degrees at tick-over and then lazily rises to only 26 degrees at 3000 rpm. Compared to the AAU, the boyer appears to have gotten things backward. Ludwig sent me an advance curve for a Boyer Micro Digital set up for a BMW that corrects all of the above; low advance at start-up (1-5 degrees), and then a TriSpark-like curve with a tick-over advance minimum of 1-5 degrees at 900 rpm. The advance is all in at 4000 rpm. I didn't reproduce the curve here because of the large differential (5-6 degrees) between the maximum advance of the BMW and the Commando. 3. The Pazon SureFire. Pazon is the only producer of electronic ignitions that publishes its advance curves. It features a very low (0 degrees) advance at start-up, but rises to 12 degrees at tick-over, 9 degrees higher than the AAU. At 3000 rpm, it matches the advance (28 degrees) of both the AAU and the TriSpark, but continues to increase its advance by another 3-4 degrees untill it is all in at 5000 rpm. I would expect the Pazon to provide a very strong, kick-back free start, and a somewhat weaker tick-over and low rpm performance compared to the AAU. It comes on very strong at higher rpms. 4. The TriSpark TriSpark features a start-up advance of 5 degrees, higher than both the AAU and Pazon, although low enough to avoid complaints of kick-back. The curve has an interesting dip in it that reduces the tick-over advance to 6 degrees or so, and then roughly follows the AAU curve, but with a few additional degrees of advance until 3000 rpm, where it matches both the AAU and Pazon advance of 28 degrees. The curve dip at tick-over likely stabilizes the idle and provides a more powerful low rpm response. The TriSpark continues to increase advance by another 2 degrees until 4000 rpm, where it is all in. I believe that the lads at TriSpark have got it right. I'm running Pazon SureFire units on my Brit bikes, and am pleased with the high-end performance, but I can feel what the curves tell me at tick-over, namely, that there is too much advance at 1000 rpm. I'd convert to TriSpark toute de suite if I could only buy their older unit with frame-mounted electronics.