I think you are trying to just change the 60 mg/ml, without altering the pg/vg ratio, to 36 mg/ml and 48 mg/ml, zero flavor juice. It would help us to know how much you want to make. That way we can tell you exactly how much of each ingredient to use. In either case you need to have some additional PG fluid and additional VG fluid. This is to maintain the PG/VG ratio in your zero flavor nic juice. How to figuire it is in the formulations above. What we don't know is how much you want to make of the 36 mg/ml juice or the 48 mg/ml juice with your quantity of 60 mg/ml juice.
If you didn't want to maintain the same ratio of PG and VG in your zero flavored 60 mg/ml nic juice it would be easy to tell you to just add some amount of VG to dilute it with. But you would still need to tell us how much you want to make so we could tell you how much to add.
By the way, you do know you can OD and die from 0.5mg - 1.0mg per kilo of body weight? This is the lethal dose in humans at least half of the time (LD-50).
Say you weigh 110 lbs, then it would only take about 25mg-50mg, taken in short time, to put you in the hospital or a coffin. That's rapidly consuming/absorbing 1-2 ml of 25mg/ml juice. How many mls of that 60mg/ml juice do you have? Be careful, it is also absorbed through the skin.