Yes, total advance should be 28 degrees @ high rpm.

Most all of the weedie engines I have converted have average power without further modifications to the intake/exhaust port timing ,and maybe the size of the bypass ports. Sometimes you're stuck with it because there is little room for modification, some engines are highly modifiable.

Rarely do I use the stock carburetor, they are almost always a little small.

Don't get me wrong, conversions are good, but 3D powerhouses they generally are not. Some of the better conversions I have done were from chainsaw engines, I think chainsaws are pretty tough duty and a weedie engine just wouldn't cut it, if you get my drift.