Havent really tried it but once and I the back end broke free and I was sideways going around a corner, wife screaming in my ear and about made me turn the car around.. So I didnt try it after that.
Easy and also difficult because adjustments change two things at once.
To use the vacuum advance we need to slow the curve around 2000 rpm, so it not all in until 3000 or higher.
Not so easy with that distributor, but its doable. Lets come back to that after you've solved the bog.
I suspect its the secondary opening too quick or too soon.