My feeling is that the relationship is more important - as long as you have a good r/s with T and it sounds like you do. It will be difficult, and I'd rather have someone I trusted with me on the journey than someone whose "technique" was good.

Since you're concerned about whether he might feel out of his depth, I'd have that conversation again and ask him to clarify. This is important enough that you need to fully understand where he's coming from so you can make a decision. Any misunderstanding or misinterpretation at this point could be a real problem. It may be as you suggested that he just wants to make sure you're up to this, instead of him questioning his ability to help you.

I've found in my own therapy that sometimes (often?) I need to have conversations with T more than once. It may be because I didn't actually get the words out right, or that I didn't fully "hear" what he was saying. Either way, I tend to misinterpret things so this ensures I get it right.