Experience will say it better.
In some case I used a small torch as assistance when I was applying the last heat shot using a pencil soldering. All depend the mass of brass you will work with.
Soldering start from big mass to less mass not the opposite.
I built all my stuff using a 40 watts pencil soldering, resistance soldering and small torch.
Silver solder is good and bad. Due the high melt point after used, make difficult to fix some mistakes. 60/40 is more easy but contain lead. personally I don't have the right recipe.
AG.