Is there something that prevent people from compiling the open source code from Gridcoin-master and running it?  If you can compile and run it, then the payout calculation is there?
A quick look of the source code, I would try to change those 2 files first, compile it and run it.

main.cpp, line 1171 for GetBlockValue, change it to "return 150;"

rpcrawtransaction.cpp, line 751, change it to "me.payout = 150;"



GRC: G2DWztx8tftUdgAPmgbns6ufm3y15JWmZe