So far, I haven't seen exactly how to link a transfer down to a blockchain transaction without continuously parsing chain tip myself. What am I missing, @steemchiller?

There is no perfect way of achieving what you want currently (I will think about this for the next update of the SDS APIs).

I guess the best way to solve this with existing APIs would be to call getHistoryByTime to retrieve the exact block number + transaction index and then call the getTransactionsInBlock. Not perfect but probably the 'cheapest' solution for now.

You also could move completely to the Account History API for watching the incoming transfers. This would make the step to get the block number for a transfer obsolete.