Bob,
You won't taste the mustard; it doesn't hold up well to the heat. Mustard is only used as a glue to adhere the rub. I've never tried Worc. sauce in that manner, but it should work fine although keep in mind it has a fairly high salt content. As far as making a difference; probably not. Your rub will have the greatest impact. Many here have started eliminating salt from their rubs. I salt my meat (apply as you normally would to eat- no more, no less) 1st, let it stand until moisture is drawn from the meat. Now my rub will adhere just fine. With this process, if you want more rub flavor, you can add more rub without spiking up the salt content. What are you cooking/smoking?
Paul