Horwath
Legend
From looking at PF1 feat that gives +1d6 sneak attack and feats in 5E are worth aproxx3× of 3.5E/PF1 feats, a full feat should be worth +3d6 sneak attack.
Looking at skill expert, skill proficiency and expertise both are worth 1/4 of a feat, give or take.
that means for every 3 SA dice traded, you should get 4 instances of suggested trade off.
it's nice that 3d6 SA is at 5th level, 6d6 at 11th and 9d6 at 17th level.
just when you get a new game tier.
so with 3rd, 6th and 9th SA dice traded, you get both options from original suggestion, while on the rest you choose one or the other.
Looking at skill expert, skill proficiency and expertise both are worth 1/4 of a feat, give or take.
that means for every 3 SA dice traded, you should get 4 instances of suggested trade off.
it's nice that 3d6 SA is at 5th level, 6d6 at 11th and 9d6 at 17th level.
just when you get a new game tier.
so with 3rd, 6th and 9th SA dice traded, you get both options from original suggestion, while on the rest you choose one or the other.