I would like to address some of the questions above.
John C,
Prof Fersht does address marks in weights on Jaques sets in his second edition of his book. I corresponded with him on this at the time.
Jaques used a 4 pronged insertion tool which was stuck into the lead to hold it to enable the weights to be easily twisted into place. the marks on the weights are sometimes deep and other times not. Usually taking the form of 4 triangular indents.
Regarding the many slight differences in knight head design on Jaques sets and their reproductions.
Jaques were using the horses head from the Elgin Marbles from part of the Parthenon Frieze which had been brought back to London and put on display in 1816 ( some think this was an act of vandalism on the part of Lord Elgin). The horse in question is the one shown dasping for breath after pulling Selene's (moon godess) charriot across the sky.
Almost all subsequent depictions are variations of this head IMHO with alterations depending on the carver's hand, apart from the so called 'drop jaw' knights introduced for a short period 1855-60 or there about. Jaques then went back to the somewhat stylised version of the Selene knight.
The earliest knights heads had smooth cheeks, the horizontal ribbing of the cheeks being introduced later in the first year of production .Some chess dealers claim to see particular differences in style as the years progress and as one can assume that as time went on Jaques used several carvers who all brought their own particular take on the heads this is easily accounted for. We do not know the names of these carvers and calling them by the names of Famous chess players avails us nothing and is somewhat insulting to those fine working men who did the carving, no doubt under difficult conditions and for long hours and not very much pay.
Vik of chessbazaar is on the point of going into production with an 1849 4.4" set in boxwood and ebony, weighted and so on. He will also be introducing other sizes and knight head variations in the future. I have collaberated with him on this and am hoping these sets will become common in chess congresses and players homes in place of some of the fairly varied in quality sets offered by other reproduction set dealers.
Polarchess.. The Dubrovnik set I have is every bit as good as the HOS set I have. The craftsmanship of both are A-1. Both sites offer excellant chess pieces. There is a new player in town & its called Chess Bazaar..! Less money for the same fine Craftsmanship & free shipping.! People just need to choose what sets they like. I am very aware that chess piece choice is a persnal decision.