If you invoke Gforth with a command line flag for the size
(see Invoking Gforth), the size you specify is stored in the
dictionary. If you save the dictionary with savesystem or create
an image with gforthmi, this size will become the default
for the resulting image file. E.g., the following will create a
fully relocatable version of gforth.fi with a 1MB dictionary:
gforthmi gforth.fi -m 1M
In other words, if you want to set the default size for the dictionary and the stacks of an image, just invoke gforthmi with the appropriate options when creating the image.
Note: For cache-friendly behaviour (i.e., good performance), you should make the sizes of the stacks modulo, say, 2K, somewhat different. E.g., the default stack sizes are: data: 16k (mod 2k=0); fp: 15.5k (mod 2k=1.5k); return: 15k(mod 2k=1k); locals: 14.5k (mod 2k=0.5k).