Ryan,
I would suggest go for ISO 14072 Organisational LCA (so called OLCA) suggested also by UNEP Life Cycle Initiative.
The benefit of OLCA is that you look at beyond carbon and widening the system boundary of standard corporate carbon footprint. The former is important in that you might have impacts that not obvious at first sight. The latter gives you benefits of assessing your products (and related supply chain including raw materials), which is the most important aspect in Scope 3 emissions in Corporate Carbon calculations, unfortunately most of the intentional or not is missed! Without such information is not really viable to set meaningful targets.
I hope this helps.