I found
*a few entries under Sherry in Ros Davies Co Down website but none connected with Drumbeg,
*variant spelling for Sherry from LibraryIreland names eg
m'sharrie 1490336 1
M'Sharrie
macsharri 1490346 1
MacSharry
macsherri 1490356 1
MacSherry
sharri 1490366 1
Sharry
sherri 1490384 1
other Sherry spellings existed eg O’Sherry.
There are other records eg in PRONI, NIFHS, on ancestryireland births but none with obvious connection to Drumbeg
I think I am correct in saying at least three times more William McSherry records exist, compared to William Sherry records.
Your Williams denomination will be important if the church record exists for your William
Did you exhaust familysearch.com
Icant help further
sorry goodluck onwards Jim