Sorry no disrespect but I dont agree. I am not soley looking at the gauge but using it as another reference tool. When the engine hesitates under slight load and the gauge shows a lean condition I feel like that is only helping determine the issue.
The VA wont fix the stumble but it will help your car run better overall once tuned properly. Your stumble is a mix of springs / transfer slot exposure / initial timing .
Try removing your carb and setting the transfer slot to a square window then set your intial timing to where the idle rpm is where you want (750ish) ... then recurve the dizzy so that mechanical advance comes in like you want. Then start changinging jets and rods...
Oh yeah ... make sure you are using the correct jetting chart. I downloadsd the wrong one once and chased my tail for a day ...lol