Witnesses please setup your price feed for gpUSD here is an open source public script down below
docker run --rm -v /path_to/config.yml:/usr/src/app/config.yml blckchnd/graphene-pricefeed graphene-pricefeed update --active-key 5xxxxxxxxxxx
there are 3 pricing sources for GPH:
(by default all 3 are active)
You can observe and remove/add them as liquidity increases, so that there is no strong disproportion of influence.