...or else get a "rough and ready" alignment by using a machinist's square against the front edge of the mill table and the appropriate edge of the indexer's base when bolting it down.
PS - Very nice job cleaning up all your cast iron surfaces!
This is what I initially did. Thank you for the additional suggestions
5C collects arrived. Got a 15 piece set that goes from 1/8" - 1".
I also got this tapper...