LEED EBOM EA c.4

Hello, I have a LEED EBOM project in Thailand. I am now dealing with EA c.4 - On site or Off site Renewable Energy. Regarding the off-site option I have the following question related to the possibility of buying Green-e certified carbon off-set (pab.207, par.3 , LEED EBOM reference guide). Do you know if can use Certified Emission Reduction (CER) from UNFCCC-- It is the gold standard for carbon credit and should be as stringent as US's carbon credit standard if not more-- or Voluntary Emission Reduction from locally-certified carbon credit ( in Thailand, it is called T-VER). Securing the carbon credit is not a big problem as there are plenty of issued carbon credits in the market. If USGBC says that only carbon credits with Green-E stamp is accepted, do you know if we can buy this credit in the US and apply to a project in Thailand? After all, 1 ton of CO2 in the US is the same with 1 ton of CO2 in Thailand. The client would like to achieve all 6 points with either On-site 12% or Off-site Renewable Energy 100%. Regarding the on-site option I have the following question: how much space would we need to install PV on the roof? And does the roof need to be within the LEED boundaries or can be nearby (outside it)? Thanks a lot!