Notes:
While examining coins in the collection at the American Numismatic Society, Mike Ringo noticed a similarity between the Voce Populi coins and a twopence token issued by Francis McMinn.  The date punches and some of the larger lettering on the McMinn token appear to match those on the Voce Populi coins.  In 1760, Francis McMinn, of Donaghadee in County Down (Ireland), issued a series of tokens, intending to compete with, and replace, the Wood's Hibernia halfpennies in circulation.  Many of McMinn's tokens were backdated to the 1720s and 1730s.

Images courtesy of Early American History Auctions

Farthing: 
Nelson 1 - Rare
Nelson 2 - Extremely Rare

Halfpenny: 
Nelson 1 - Rarity 7- (10-13 known)
Nelson 2 - Rarity 3 (Scarce)
Nelson 3 - Rarity 3 (Scarce)
Nelson 4 - Rarity 3 (Scarce)
Nelson 5 - No verified examples exist
Nelson 6 - Rarity 5 (31-75 known)
Nelson 6a - No verified examples exist
Nelson 7 - Rarity 6 (13-30 known)
Nelson 8 - Rarity 6+ (<16 known)
Nelson 9 - Rarity 3 (Scarce)
Nelson 10 - Rarity 5 (31-75 known)
Nelson 11 - Rarity 4 (76-200 known)
Nelson 12 - Rarity 3 (Scarce)
Nelson 13 - Rarity 4 (76-200 known)
Nelson 14 - Rarity 6 (13-30 known)
Nelson 15 - Rarity 4 (76-200 known)
Nelson 16 - Rarity 7+ (5 known)

Significant examples:
In the February 2005 issue of NUMISMATIST (page 63), William Anton offered a Voce Populi Small Letters Farthing for $175,000.00, describing it as follows: "Finer of two known.  Abt Unc."

Sources and/or recommended reading:
"Descriptions Of Die Varieties" by Zelinka, The Colonial Newsletter, October 1976, pages 559-564

Rarity ratings by Stan Stephens (posting by at colonial-coins@yahoogroups.com, August 30, 2004, Message 26963

Email message from Mike Ringo, November 16, 2004