Ho youri_v
You can see how many features each image has in the 1Ds view.
You cannot force RC to use those images with CPs alone - RC needs to find the matches by itself. So if you can’t convince it, it won’t do it. Using CPs is a good way to achieve that, but no guaranty for success. The (in most cases) quickest and easiest way is to take more images in the problematic area.
Your questions about the automatic CP placement are answered in the help. They are only suggestions and you need to adjust them if neccessary. You do not need to use them all and you can also use other images that are not being suggested. That one has to click every suggestion individually has been criticised resently here:
You need to try and see for yourself if the suggested changing of the feature source will help your model along - it is different in every case. Keep in mind that already existing components will influence the newly calculated ones. So if you don’t make any headway anymore, you can try and delete all (make sure you can undo that though) end re-align. Sometimes this will result in a larger component, especially if you have added control points before.