Hello Joe; first let me say how very sorry I am that you and your family are going through this. I am so gald you are getting some help with processing losing your father; this is big and I think you deserve a lot of credit for recognizing how hard it is now and how hard you expect it to be when he leaves this physical world.
I don't want to sound wishy washy, but I really think you need to trust your instincts on what you want to do and what will be important so that you hopefully don't have any regrets later. As I faced the death of my father, I spent time with him at the end of his life, telling him things that I wanted to be sure he knew and sharing happy memories and music with him. Since he was not able to talk at the end, I asked him to nod if he could hear me, which he did. In other words, I said my goodbyes when he was still alive. When I got the call that he had died (yes, in the middle of the night) I did not need to go and see his body. I had said my goodbyes. That said, the funeral home told me I needed to confirm Dad's identity there, so that turned out to be another chance to say a blessing over him.
When my mother died, I did go to see her, as we had a different relationship and I wanted to hold her one more time. Different approaches based on what felt right to me for each of them.
Perhaps it will help to search your heart to decide what feels right for you in the case of saying goodbye to your father. There is no right or wrong, only what you know in your heart is right for you.
After your father dies, there will be lots of time for you to consider how to honour him, his life and all that he meant to you. That could be something concrete like planting a tree or it could just be what you want to emulate of the way he lived.
It sounds like you are a wonderful, loving son and that is the greatest gift you could ever give your Dad.
I wish you peace as this difficult time comes to an end and a new phase emerges.
Take good care.