Since you all have been helpful in teaching me the ways of smoking, I'll help out with an easy rub recipe for true Santa Maria grilling. The following recipe is my take on Susie Q's Santa Maria Seasoning, which is the "original" Santa Maria seasoning. I started doing this when I moved to the east coast and couldn't get Susie Q's anywhere. I've tested this over decades and I think it's pretty spot on. Even if it's not perfect, it tastes great on a tri tip or any grilled steak.
Santa Maria Seasoning
4 T Salt, coarse ground
2 tsp Black pepper ground
2 tsp Garlic powder
2 tsp Dried Parsley, minced
1 tsp Sugar
It looks like a lot of salt. And it is, but it's the proportions they use. Also, since they rub it on just before cooking, it doesn't get into the meat that deeply, so you get great beef flavor on the inside and a salty, garlicky, slightly sweet crust. It balances nicely.
Added bonus note: A proper Santa Maria BBQ includes slices of french bread (toasted on the grill) and dipped in butter. A few years back, I was visiting a relative who has a ranch in the Santa Maria area. I noticed that they had put a couple of roughly chopped garlic cloves and some salt (like a heavy pinch) in the pan they use for melting the butter. Tried it at home and it makes a huge difference. Don't let the butter get hot enough that the garlic browns, just warm it up and let it steep for a while. The flavors pop nicely.