Help and advice needed with 65 C20

[openroadcustoms]

Hi
I just got a 1965 C20.I understand it was the camper but the back is missing.It is a good looking truck considereing age.I want to start changing it.Firstly lowering it.

What is the lowest I can take it with just coils?
Will that change stance and handling

I am in South Africa,so parts is a bit hard to come by.What coils can I use?
I would love to take it down 4-5 inches later this year if possible.

Any advice and help would be appreciated.

Thanks