Brian/Bob--
Salt will draw moisture to the surface of the meat. I make rubs without salt, salt the meat, allow it to get good and moist, and then apply the rub. The moisture allows the rub to stick. If I want more rub applied I just wait a little while for the first application to moisten and apply more rub over it. Salting the meat separately allows me to apply as much or as little rub as I want without worrying about the resulting salt level (which would be a concern if salt was included in the rub).
Technically, because of the moisture issue, salt can impede caramelization and one sees admonitions to avoid its use when caramelization is intended. Nonsense. Most of the time browning is achieved over high heat (pan-fried chicken breast or grilled-sirect steak, e.g.) that whatever delay might be caused by the salt is irrelevant or, in the case of low/slow cooking, with sufficient time so that caramelization will occur regardless.
Rick--
I'm not familiar with your source so I can't say. I use Penzey's because I like their quality so much and because I can get origin-specific herbs and spices (Turkish oregano, Sri Lankan or Vietnamese cinnamons, Sarawak white peppercorns, e.g., which is important to me as source differences can mean significant flavor differences) rather than just 'oregano', 'cinnamon' and 'white peppercorns'. It might be worth comparing a couple key ingredients from them with Caputo side by side and seeing if the difference(s)--if any--are enough to justify purchase of more expensive products. (If so, you might contact Penzey's directly--either their main facility or the store nearest you) to see if you can't negotiate a price break. (I'd try a store first, in person.)
The other thing to try, as noted above, is a substitution of more flavorful ingredients for those with less. Though I use paprika in some rubs it is more as a carrier than as a key flavor. For rubs where I want a significant chile component I use a blend of dried peppers which might include ancho, guajillo, cascabel, chiles de arbol, Aleppo, a few varieties of New Mexican, dundicuts, habs, jals, et. al. Some of these add heat too so I skip the cayenne.
My point is that, while playing with rub ingredients--in terms of quality or substitutions or both--you might very well develop recipes that have more of the flavor profile you seek that actually cost less because less quantities are used. This is very much what I've found in developing scores of rubs (for Q and not) over the years.