Adobe Central to Adobe Experience Manager 6.3 migration

We're looking for migrating thousands of Central Output Server family forms/templates to AEM forms/templates. We are trying AEM designer import function to import Central forms. Its helping us with conversion but its not doing it perfectly right, means not 100% correct. By import, we're achieving near about 80%. We need to manually match it to its perfectness. Its taking long time to do it manually hence we're looking for some automations script. So queries are

1. Is it possible to achieve 100% correct conversion using AEM import? if not what are the reasons? If yes, any suggestions/tricks.
2. Can we write any automation script/program using any language? I mean will it be possible or are there any constraints with AEM & Central?

Kindly help.

Thanks in advance