SingTel does not have “Tag Lite” mentioned anywhere on their webpages. The only way to know more about it is to go to any SingTel Hello Stores. I first got to know it when I was surfing Hardware Zone Forums and specifically in the “MultiSIM with SingTel to use on iPad” thread.
Tag Lite Supplementary Plan allows users to share bundled data between supplementary line and main line.
Finally, SingTel now support MicroSIM cards in their MultiSIM plans, however the price is 2x more expensive the normal SIM cards and from the description on the VAS page under “Others” tab, it was mentioned that then can be only 1 MicroSIM card in any combination of MultiSIM.
So if you got 4 SIM cards, only 1 of them can be MicroSIM and the other 3 is normal SIM. Perhaps it is due to the initial hight stock demand. But I believed that it will change eventually once the dust has settle.