In the end, how to handle the situation is up to you. There are multiple ways to do it, but I can see two main options here.
Posting a community wiki answer yourself and accepting that is a possible way of documenting the parts of the posted answers that you went with, but since community wiki answers float only based on community votes, lots of people might not even notice it even if you do accept it. Also, since it wouldn't add anything new, but rather just repeat content from other answers, it might be seen as a not very constructive contribution.
The other alternative is to simply not accept any answer at all. While answer acceptance is nice, nothing forces you to accept an answer to a question. I have a few questions where I am in the same boat; multiple answers all making good points that contributed to the path I took. In such a situation, picking the single answer that helped the most can (as you have found) be very difficult, and perhaps the best choice then is to not pick any one single answer at all. Take the parts from each that helped you the most, vote up those answers, proceed with building your world, and let the votes from the community do the rest of sorting answers for future visitors.
If you are posting an answer and adding a solution of your own then you can of course accept that. But in that case, you might not (probably don't) want to make your answer community wiki.