Larry, my instructions for my Stehls twin horn claim that it should be in the 25k area using at least 30% for 10 minutes. Then it says to wait until the black oil stops coming out then switch to 40% . I believe Larry Driskill says to use a 5 1/4 x3 cut down to 4 inches for the VA mk II break in. You want to pay particular attention to the crank fit as I think these engines were also prone to that problem initially. I haven't run mine yet but I'm looking forward to it. The one that were using now is in the 28 k area. I surely wish these were readily available. The other noteable point of interest in that engine is the carrier that houses the shims under the piston. You may want to check that its tight as these also have come loose. SOme suggested Locktite but I believe that didn't help much. I'm sure its just something you should maintenance now and again. Ken

I have 2 of the VAs, don't know if they're I or II, but using pressure they are hot little engines.  They keep up with my Norvel .061s. 

Out of curiosity I tried suction feed, not really expecting much, and sure enough they will run but not reliably on suction alone.  I guess a guy could choke down the venturi and get better results. but it seems a shame to limit a high-performance engine like that when there's so many others available already designed for sport/stunt.

I agree with your conclusion in spades. Very nice combo.

I would add:  6x2 prop, 200-250 sq. in. wing, 10-12 oz., 45-48' lines, light wind, compete with the best. On teaspoons of fuel. And an engine that won't amputate if you get careless.  Why aren't there more of us?