Hmm, unless I'm mistaken, it sounds like your designs currently exist in a smaller or thumbnail-sketch form* — which would mean you might not need tracing paper. Simply enlarging your designs to a 1:1 scale wouldn't require tracing.
That said, I've found that I prefer lighter-weight tracing paper over medium weight. The heavier weights tend to have a toothier texture which doesn't help keep pencil lines sharp and smudge free. Also, if you're using a lot, a roll will give you better value than a pad of individual sheets. I've used Bee Paper (available on Amazon), and I know that some people even order those rolls of paper used in the doctor's office on the exam tables.
* If your designs are digital, then my suggestion is to make an actual-size mock. Scale them up on the computer until they are 1:1 scale (actual size), and then print the design at 100%, tiled across as many pages as you need. Some printers or programs allow you to customize how much overlap you need across each sheet of paper; this is a helpful feature because most printers can't print full bleed (edge-to-edge). Once printed, you just cut off the white margins (where the printer was unable to print), and then use the overlap to match everything together.