Sure thing, Zardoz, you're quite welcome.
Though I've said it before, perhaps this is a good time to reiterate. The author of these German plans, clearly consulted Payne-Gallwey's work, which is, by and large, pretty good for its time (1907) The biggest error he committed in his Flemish arbalest pattern lies in the nut and socket. He fits the nut in a steel socket, made to order, and that will work okay, but unless you're really building a 1200 lb. siege-bow, you can use a bone-reinforced socket instead.
PG's roller nut is 1.5 inches in diameter, a reasonable size for a strong bow, but he only sinks that roller in the stock by 3/16 inch. (approx 3/5ths) You'll be much happier if you bury the nut by 2/3 rather than 3/5ths, unless you happen to have a carefully matched steel socket, like PG. If you make the nut as deep as 3/4 of its diameter, you'll have trouble taking it out of the top of the socket. At 2/3 below top-line, you'll have no troubles there.
Second point... if you put the sear-pin just behind bottom-center of the lock... a quarter-inch will suffice, rather than at dead-center, your trigger will take up some of the load the socket would otherwise handle, and most importantly, the trigger will prevent the nut from trying to rise out of the socket when under load from the string. This means you have less stress on the edges of the socket and it lasts lots longer without any adjustment or repair.
Last point, and this is one PG gets right, you DON"T want the sear cut all the way across the bottom of your roller-nut. Go to the extra trouble of cutting a pocket in the bottom of the roller, and fitting a steel pin or block for the trigger to work against. A notch all the way across the bottom will be a stress-point, which can lead to the nut's splitting vertically, from the backs of the lugs, right down through the sear-slot. That's why I drill and tap the roller from top to bottom and screw in a piece of allthread. Period bowyers didn't have allthread, so they had to use a chunk of iron or steel, but in fact, allthread makes it really easy to remove a worn or damaged sear and replace with another. Whatever you do for a sear, it really helps to leave the roller-nut round at the bottom. It will run much smoother with less oscillation on release.
So does that make sense? Geezer.