I used to do that and it would still get freezer burn or it was too small and I couldn't find it in my freezer. I have used the pink pickled ginger for years now and it works perfectly in any recipe that I make and is always ready to go in my fridge.
I have not used a packaged spice rub but I know that there are many very good ones out there. I am doing pork chops tonight with spices that I brought back from Morocco...they are a bit old so I just use more and I think it will be fine. I am pretty loosey-goosey with recipes and measurements etc. That's why I don't try to bake...too precise.