It is insufferably confusing unless all baselines in a subarray have the
same values of this set of parameters. They are therefore forbidden to
occur inside a {...} for(..) block.
There would be something to be said to make this stuff into a special
$CORRELATOR block, like $SOURCE. For one thing, it would make it very
natural to supply ahead of time to a 'filler' program a list of all
settups to be expected, which would make it easier to write than having
to have it be ready for anything at all times.