Use any loop for phantom, no license, go in LD 22 and slt you will see that you have a total of 65535 some thing like this example:
PHANTOM PORTS 65535 LEFT 65512 USED 23
How many well that depends what else you have so everything takes loops so Media Gateways, PRIs, TDS, CONF, Virtual loops for IP sets and trunks, etc. but as you can config 512 on every loop how many do you want?