Id say that Commerce and Patronage are about even.
I would argue that the most significant difference is that Patronage needs just two picks to be extremely valuable, for the +20 resting point. CS friend status is easy even with Siam or Alex in the game. (Yes, Ally status is much more competitive. But it's not necessary except for DiploV.)
One challenge with Commerce is that you need three picks to get the most valuable one. I think the Commerce opener is stronger than the Patronage opener, so if I think I will just have one pick, my preference is for Commerce nowadays.
But OP is asking about seriously coming back to the second three -- and this is where I think things get tricky. The finisher is great, but the other challenge with Commerce is that a couple picks are weak to the point of being almost useless.
So for OP, I think Patronage works out best -- since every pick is good.