Phil, I asked about location because I've done well at Flea markets, a great Petzval for £20 ($31) 6 months ago actually from someone I know through camera fairs as well. It's quite large & heavy but was in apparently poor condition - it cleaned up beautifully and is optically perfect but it only covers 5x4 maybe half plate.
This last Easter Monday at the same Antiques & Flea market I found a nice 8" RR but coverage won't be more than half plate, again it looked poor in terms of the brass work but again has cleaned up well. Both thease lenses had no Waterhouse stops but it's easy to make your own. The stall holder at Mondays Antiue/Flea market had another 3 brass lenses but the rest were projection with no diaphram or slot for Waterhouse stops.
Yes your friends are right it is a case of waiting and these lenses are available at the right sort of price, but it helps to put yourself in places where that might happen Flea markets, Camera fairs, swap meeets even antique shops. It's very rare that I don't come away with some real bargains at Flea markets and Camera Fairs - the same seller I had the 8" RR off sold me a Rolleiflex Automat for £80 ($125) his marked price was £155