How to Set OLTC Tap Positions, Step Size, Min/Max in IPSA for Voltage Drop Correction?

Hi,
I have a network with hundreds of busbars (ranging from 33kV to 6.6kV). I have some electrical loads connected at the far end of the network via 2-winding transformers and I am analysing the voltage drops at the point of load connections.Some of these busbars experience around 10% voltage drops  (0.90 pu) therefore I want to add tap changers on my transformers (I am using IPSA simulation tool). There are some settings I need to change as follows:
Basic tap data:
Setting (%) = Current tap position
Minimum (%) = Minimum tap position
Maximum (%) = Maximum tap position
Step (%) = Tap change incrementWhich of these should I vary to improve voltage profiles? Also what are the ideal values I should set for the above data?

Thanks.

Berk, I can't answer this but some guys I work with may be able to (I work for a power company).  Please be patient and I will try and get an answer for you.

Berk sorry, none of the guys I asked had the expertise to answer your question, I will keep trying but I'd suggest you try elsewhere.  (I'd point out that our primary focus here is electronics, not electrics...)