Need help with stamp tool after update

I have asked this in many places and not gotten a single reply.

I have used the stamp tool before using the free stamps from SouthernGFX and following his tutorial, setting the alpha falloff to custom replicating his little “table” (if you have watched his youtube you would know that is what he called how it looks).
In the previous version it worked well

In the new version under falloff there is Presset, CatMull-Rom and Spline
Neither CatMull-Rom nor Spline seem to have the same effect as custom used to. Clearly I’m doing something wrong or missing some other setting.

I’d like to possibly purchase other brushes or add ons for Nomad, but not if I can’t get what I have to work.