It Doesn't really matter what kind of tomato it is. Also, Can anyone tell me if red and yellow currant is good?
You can find what you are looking for in this thread or send a message to brokenbar.
As for the currant tomatoes, I make a point of not growing them because the production is very low and they tend to cross with normal tomatoes at a very high rate.
There really is no "best" but there are literally hundreds of "great" ones. So you will want to define your criteria/needs a great deal more.
The thread linked for you above offers some great choices.
Currants - agree they are problematic and not worth the trouble IMO. Especially in your zone where thousands of varieties will do and be so much better.
I have not dried tomatoes, but I did follow that link and Brokenbar suggested Opalka for drying. I cannot comment because again, I have not dried tomatoes, and frankly don't care to consume them. However, I do make tomato sauce (from all types of tomatoes) and my favorite tomato for sauce is Opalka. Given Brokenbar suggests it for drying and I can recommend it for sauce/cooking it might fit the bill for you. It has very few seeds and is not juicy. It makes a naturally thick sauce. They taste lovely cooked (or fresh - or in salsa) too. You mention heirloom in the subject... and I'm not sure if it's an heirloom, but it's OP... You don't know me, but I'm particular about my tomatoes and I LOVE opalka.
Hope this is helpful. Good luck in your quest.