David, supposedly a parallel works like a conjunction, when you consider how the two planets would be situated in the sky. A contra-parallel, with both planets at the same degree but one north and one south, works like an opposition.
As to which one would be stronger, I think we have to look at the planets involved. A contra-parallel involving the moon and Venus, for example, would probably be less troublesome than one involving Saturn and Pluto.
Aa Dr. Farr mentioned, you can look up celebrity charts at Astrodienst on their Astro-DataBank, click on the small chart for an enlargement with an aspectarian, and then that second page allows you to add "additional tables" that give declination.
Saturn, as you know, was the traditional bringer of miserable things. Liz Greene cleared up a lot of that with her book Saturn: A New Look at an Old Devil. Unfortunately the New Age, evolutionary, and theosophical astrologers dissed Saturn again, by seeing it as too limiting and material. The modern outers supposedly were terribly superior to Grandpa Saturn.
Which I think is ridiculous in its own way. Each planet has its themes, and each can have an empowering or disempowering expression.