Here we have Donald Featherstone passing on some of PG's ideas for concealment and surprise to readers of Wargamers Newsletter. This article dates back to Issue 18 - which must be from late 1963 (given that Featherstone began publishing Newsletter in '62) - and is the earliest piece by, or about, Peter Gilder that i have come across to date.
As you might expect PG's ideas are simple but effective. I particularly like his 'unit counters' concept - reminds me of Koenig Krieg (which remain my favoured SYW 'big battle' rules).
This article comes to us via Harry Pearson and Clive - thanks guys.