Coregistration of 1.1 ALOS PALSAR products

I have 2 ALOS 1, 1.1 products. I am trying to coregister them for InSAR, using the InSAR coregistration tool (they are a pair that should be suitable for this purpose). I used the ALOS Deskewing tool on both, then created a smaller subset of one image to use as the ‘master’. However, I am struggling to get a good coregistration. I have tried to use available tutorials to figure out the process on the ESA website, but I’m still ending up with a stack that doesn’t line up. Does anyone have any tips for achieving a good coregistration? Perhaps pertaining to the “Resample” tab? I am not sure if I’m making the right decisions there. I have already been told to choose a large course registration window, which I am applying.

Co-registration will fail over water or areas that have very few features and the coherence is very low. You might have a better chance of finding matches by using the whole scene (or at least a large piece) instead of a small subset.