Hi,

There should be no problem in using system having two independent circuits, in addition they give better efficiency and more advantageous than the single circuit.Mostly, one compressor starts after another and have no idea about how they can be start at the same time.8 Ton package units can be used for piping upto 30-35 foot , if you want to increase the length of piping , then you have to charge some more refrigerant in the system.I don't know much about Bangladesh ,but here in India generally we use BlueStar package units.

Have a nice day.