Buying mods for speed secondaries, looking for some advice

My best speed secondary is +22. That was really lucky. That one had 2 adds of 6 and 1 of 5. I have never seen one start at 6, but rarely see them add +6. From that, I would estimate that 5 +6+6+6+6 for a total of 29 would be the best you could get.

Of course, the odds of getting that are much worse than winning the lottery. I feel like won the lottery with my +22, especially since it is on a speed set.