change to MCMCspec defaults for MV nodes
change to MCMCspec defaults for MV nodes

nxdao2000/nimble,NLMichaud/nimble,NLMichaud/nimble,nxdao2000/nimble,NLMichaud/nimble,nxdao2000/nimble,nxdao2000/nimble,nimble-dev/nimble,nimble-dev/nimble,NLMichaud/nimble,nimble-dev/nimble,nimble-dev/nimble,nimble-dev/nimble