Thera band Black question.

Hi there.

I am thinking of trying thera black for the first time .

My favorite is Thera gold and my prefered draw weight is 7-10 pounds .I want thera black with the same draw weight I would use the same tapering ratio.

Question is :How much faster would the Thera black be then the gold? If there is any dif at all.

Ammo 8mm steal 9.5mm steal draw lenght 71 cm.
Average life for thera black?

Thanks