I think the answer to your question depends a lot on you, and how your body happens to handle fasting. As I have a good bit of person experience with fasting, I can share my experience and maybe you will find some of it helpful to you.
I've been practicing intermittent fasting for 15+ years, long before I'd ever heard about it, just due to my schedule and not feeling a great need to eat set amounts at set times. So I'd guess that my body is pretty good at burning fat. I've also done multiple 1-11 day long fasts. Some with just water and some drinking juice and tea. I usually feel pretty hungry for the first two or three days, and then the hunger feeling pretty much goes away. On day eleven of the one 11 day fast I've done, that hungry feeling came back quite strongly which is why I ended that one there. I did not have that experience with the previous 10 day fast I'd done, but I wasn't quite as lean then so that may had made the difference.
I usually look and feel a little leaner, but don't loose much weight. Maybe 2-8 pounds depending on the length of the fast, but that's kind of hard for me to measure as my weight normally fluctuates around in a 7ish pound range on a normal day to day basis. The very first time I did a really long fast (10 days) I might have noticed a slight weight gain afterwards, but I'm not even sure about that, again due to my normal fluctuation in weight. But most of the time, I jump right back into eating like a horse, which I've certainly heard is not recommended, but has never seemed to be a problem for me. And stay at the lower weight for a little bit, then gradually return to my normal weight. I'm female, 5'8", and weigh about 130 lbs. if I pick the middle of my normal weight range. So I'm not trying to loose weight and returning to normal is fine for me. If I wanted to keep it off I think it would be a bit hard, but may not be if you think you have weight to loose in the first place. I don't really know.
Loosing muscle mass I haven't really noticed. When doing crossfit the whole way through a long fast I tend to loose some endurance, but I don't know if it's really loosing muscle as the day I start eating again, it seems to go back to normal. But I am a woman and we usually have more body fat hanging around, so a man may start to burn muscle more rapidly?
Hopefully some part of that you can find helpful, but I do think everyone's body is different. My opinion would be that if you're feeling fine now, 60 hours is going to be fine for you, but that is just my opinion. Good luck! And I'd be interested to hear what you decide and how it worked out for you sometime.