String Sizing calculation

[javcerty]

I see a number of String sizing tools out there.
An e.g. : http://www.fronius.com/froniusdownload/tool.html

Does anyone have information/formula/site to know how the min/max modules for a given inverter are calculated ?
I'd like to do the calculations myself without using the sizing tools ?

To the best of my knowledge , these are the factors that should go in to calculate the Min/Max Modules :
1) Module's Voc , Vmp
2) Module's Temp Co-efficient
3) Highest and Lowest temp for the jurisdiction
4) Inverter's Highest acceptable voltage (to determine max modules)
5) Inverter's Startup voltage (to determine min modules)

Anything else ?

Thanks in advance

[Mike90250]

Many of the string sizers, are developed by the hosting company, to protect their expensive gear from abuse. They rely on published specs to develop look-up tables for many configurations.

[Naptown]

You can do it yourself but why?
I have a spreadsheet around somewhere I used to use but selecting the module and location is sooooo much easier