The best measurement of how much you spent in 8 gates is the training points. Because usually you can keep good track of how much of that you spend and you can see how much you have left.

Personally, I have 11 reds at 210k training point (I think I've ditched 1-2, so maybe 12-13 instead), so it's roughly 1 per 20k.

Given that I only have 10 maxed gold, rest being at 10 (all red being 9, 4 purple quick at 11), you might have more training than I do, if you have 4 sets of maxed gold. So it would be an extreme case of bad luck...