Not a developer so may well be a stupid question…but
theoretically, could one replace a full-fat bitcoind with something like this: https://github.com/gdassori/spruned when running a counterparty full node? (seems to have all the emulated API calls indexd-server needs)
another question, projects like  say their external index DB comes to around 20% of the filesize of bitcoin block databases on disk. Whereas the counterparty node setup instructions report a diskspace requirement almost the size of the diskspace the bitcoin databases themselves takeup. Is this because the index used in  is storing only a subset of the information the indexd-server does/needs to store? or could the counterparty external index be theoretically made smaller in order to lighten the HD footprint for those with more limited hardware.