All things being equal, Gold level vs High End...

Hopefully I can ask this question in a way that makes sense. All things being equal, what difference in level of Gold vs. HE should always result in the Gold being selected?

For example, if I have a level 8 gold driver with green shells and level 6 HE driver with green shells, should I always go gold or HE? What about 8 gold vs. 5 HE? and so on. What is the minimum difference that has you choose gold over HE?

And does it work the same across DKG or is there a different calculation across the three?

Another way to look at this is what is the starting % of each tier, because each of the cards just say, for example, "+2% chance" but I don't know what the starting % is for each of HE, Gold, Silver.

Thanks!