I have built a lot of pads over the years. Mostly H. Some U or O. I never got into the math of calculating them. There are charts everywhere or online calculators to figure the loss and values needed.
With about any console you stick a good LD mic inside a kick or put a decent mic on snare and you probably will wish you had a pad. I have one install with DSnake on a 24 that I have pad in and still dialed way back on gain. Mic doesn’t have a pad.