I know methadone has a long half life so I just wanted to make sure if it's okay to redose 60mgs 16-18hrs after taking 50mg. I know it's probably a trival question, I just want to be on the safe side. Thanks for any input, I really apperciate it.

You will most likely be safe taking the other 60 mg seeing as your opiate tollerance should be up from the 50 mg. If you feel unsafe start out with 40 mg and take 20 more mg a couple hours later.

If it is still holding you over it is still in your system. The half life varys from person to person but it builds up in the system over time. But if you have just taken it one day then just dose 40- 50 mgs.
I have taken it for like a week before. I would take a steady dose of 50 mgs the first few days and it would build up then the next few days I would need only 30-40mgs because it was built up. When I am less active I have noticed it last longer due to mmy metabolism being slower(les physical activity).
You may even want to start with less because methadone is very strong and has resulted in quite a few deaths because of the strong sedation it causes.

I would start out with 20-30mgs just to be safe if I were you. it will probably be enough since you still have it in your system.