Just last weekend, I had a desperate need to control geometry for a
self-running demo on Monday :-). I tried just about everything, and
found a way to do it.
In app-defaults, or .Xdefaults, or (as I did) merged into xrdb, set the
following X resource:
XMosaic*geometry: WxH+X+Y
where W, H, X, and Y are the usual parameters for a -geometry command line
argument.
-- -Brian Smithson brian@eit.com Enterprise Integration Technologies +1 415 617 8009 459 Hamilton Avenue, Palo Alto, CA 94301 USA FAX +1 415 617 8019