I've been a fan of V. M. Starr's loading recommendation for a couple of decades now. Here's the column in my 20ga x 44" Getz: powder, TWO spit-lubed OVERPOWDER cards, shot, one spit-lubed overpowder card. Equal volumes of FFg and #6 shot. Been using the same measure so long I can't remember, but I think it's about a 70 grain measure. If cold and afield, lube the cards with whatever suits your fancy. As you can tell by the number of various and sundry recommendations for lube concoctions, it apparently doesn't matter much what slippery goo you choose. Fats, oils, water, soap, alcohol, peroxide, don't use X, never use Y, Z is essential. I'm always amazed at the range of recipes for lube that appear whenever questions get asked!
My disclaimer: Your mileage WILL vary...