That post seems to have disappeared, but if whoever is still watching, try this.... your mileage may vary.

Tip: Lower the Drum Sample Pitch.

You'll get a looser, rounder, "flubbier" sound.

Not because Drums in the 60's were flubbier sounding, but because Studio Producers often played around with Recorded Tempos by speeding up, or more often slowing down the Tape Speed. Sometimes to get an intentional change of Pitch or Musical Key. By design or accident, it happened a lot.

Another aspect was Tape Saturation... warm and kind of "blurred around the edges". The Strymon "Deco" has become popular for (one of) its selling point of creating "Tape Saturation". I recommend studying the Tape Saturation subject on the web for more "60's" ideas.