Hi,
Please take a look first at:
Cisco CallManager SRND guide:
www.cisco.com/go/srnd
The important option here is the CallManager Capacity tool, this is what you are looking for.
This will give you all the options you need including MCS servers quantity, model and the info requested aboved. Also takes into account other variables as CTI devices and Gateways.
http://www.cisco.com/cgi-bin/CT/CCMCT/ct.cgi
Check for Telco connectivity
http://www.cisco.com/univercd/cc/td/doc/product/voice/c_callmg/4_2/sys_ad/4_2_3/ccmsys/a08gw.htm