Ok so here it goes.
First and most important. BREATHE... She doesn't know she's any different. DO NOT FEEL SORRY FOR HER! She is a normal dog with "diff-abilities" she is not disabled. She can function almost like any other dog. You need to not get hung up on her issues. Just quit thinking about it. She can be trained through touch and light and smells. Expect things from her like you would any other dog you have had... well, except recall lol.
Ok, so with that out of the way, I have some questions. You say she has a little sight? Does she movement? Light? Shapes? Does she bump into alot of stuff? Does she follow you around? How old is she? Do you have other dogs? Is she food motivated? Does she play play with toys? I can't give alot of advice without knowing these things so I can tailor the training to her specific needs.
I'm going to tell you alittle about mine. Mouse is a female I adopted at 5.5 months old.... she is the happiest dog I know! You wouldn't notice that she is totally deaf and her eyesight is pathetic at best. She has learned about 30 tricks and behaviours and plays with my other dogs and cat like normal. She's almost 5 now. I clicker train her using a flash of light as a "click" she has to think about what I want and teach herself the trick, just by getting clicks as feedback. Boo is a bit different. He is deaf but can see ok, tho he does have some vision impairment. He was spoiled and never expected to learn anything or follow the rules, so he's a bit of a jerk to train lol. I also have a deaf cat and a hearing dog.
Mouse and I just spent the day at a neighbours baking, and she made several comments on how if she didn't know Mouse had issues, she would think she was completely normal. She snooped, kept an eye on us and the food, played with her dog and generally just did dog things. She was very good. I expect her to behave and obey, so she does.
I have a ton of videos of my deaf dogs and training vids and such. I'll post a couple for you. And I can make you one about any specific training question you have.
A friend of mine from fb and I are in the process of starting a group and getting a bunch of info together specifically for doubles. We've got the group up, but haven't finished adding tje info and such. Look it up. Just search for double dapple dachshund. It's the only one... and we have all of three members now lol. But we can do alot for you there, and post a bunch of info... hopefully we'll get a bunch of people with doubles so we can help eachother out.
I eagerly await your answers so I can help you more specifically!