I forget how old Clyde is. I'm glad you are getting all of the needed tests. I support your decision to bring Clyde home and let him live things out where he is most comfortable.
Two years ago I made the decision to put down two of my dogs. (I'm not suggesting you put Clyde down.) They were bro/sis and 15-1/2 years old. Health was affecting both of them and it had gotten to the point where I felt their quality of life was not at the level where they were comfortable anymore. I did not want to keep them alive just for my need to have them with me.
Once I made the decision and the appointment for them, I spent their final week with a Celebration of Life attitude. They were heavily medicated, so they weren't in pain. I gave them special treats, took them to the park, paid a lot of attention to them.
I even sent out party invitations. I had a Picnic in the Park for them the day before their appointment to go to Rainbow Bridge. They always loved going to work with me. They had a good time at work and everyone paid lots of attention to them. They got Kid's Meals from Jack in the Box. Even my boss walked over to the park to show his respect for them. They were as happy as I had ever seen them. (heavy meds are great!)
I knew that I had done everything I could for them and they both had wonderful and long lives. I buried them together, with everything they needed for their journey. I sat and talked to them as I added each item to their resting place. Water in case of thirst, food in case of hunger, their favorite toys, etc. I just talked to them and enjoyed the last look of them snuggled together. I then burned sage over them and said my prayers.
There was a lot of closure for me by approaching their last day proactively. I have pictures in my office that were taken of them at their Picnic in the Park. The joy in their faces continues to be a comfort to ME.
I wanted to share my experience with you, because it sounds like you have pretty much the same plan in mind for Clyde. It is so important that we make the decision to do what is best for our pet, our friend, instead of being selfish and allowing them to live beyond the quality of life. It's just not fair to someone who has been our best friend(s) for years and years. They deserve the best we can give them.
May Clyde have a wonderful rest of his life and I hope that he does not have too much pain. It sounds like you will know when it is time and will do the right thing for Clyde.
I will keep Clyde in my thoughts and prayers and you also.
Judy