I would choose a non-purple variety given the ones you already have there. All but Abundance are purple/blue (though VV also has white). How about another pink or a white? Viticella/type 3's that would fit this would be:

Mrs. T. Lundell
Margot Koster
Comtesse de Bouchaud
Hagley Hybrid
Tentel
Madame Baron Veillard
Alba Luxurians

If you need to choose one of those three, Vesuvius (Galore) is a great, strong grower, though Polish Spirit is a tried and tested cultivar.

Betty Corning is the same color as Prince Charles but has much smaller flowers that are scented. One of my faves.

Minuet and Tango have small variegated flowers

Huldine and Alba Luxurians are nice whites

Thanks everyone for your help. I think most of the ones I have on the wall are burgundy red shade. I ended up moving my small Jackmanii to the spot, after going on a clematis shopping trip to the local garden center! I bought Amethyst Beauty and Vienetta, to plant in Jackmanii's old spot. So far, I just moved Jackmanii, but haven't planted the new ones because it doesn't stop raining here in Ohio. Thanks again for the help!

Polish Spirit is a huge growing dark purple. Blooms longer for me than Etoile Violette but looks very similar.

Last year Galore was a blooming machine for me. It would be my choice.

However in the case of your wall I would add Betty Corning for a blue color, just don't put next to Prince Charles.

Katie