The standard saddle width for a Westerly-built Guild acoustic was 3/32". Prior to learning to make my own bone saddles, I used
Bob Colosi's "Standard Martin Drop-in Saddles"... They are 3/32" thick, and a bit longer than a Guild saddle. The radius seemed to match that of my Guild Dreads pretty well. Bob supplies good instructions for fitting them to a Martin guitar, and they are pretty easy to adapt to a Guild with just a hobby razor saw and some sandpaper:
First, trim them to length with the razor saw, such that the compensation will be properly placed under the b (2nd) string (you trim a bit off each end, then round the end off a bit for aesthetics).
Second, sand them to fit the slot on your Guild. Bob supplies them a little thick, so you can sand them to the appropriate thickness: which is not so thick you have to force them into the slot, and they can easily be removed with your fingers, but if you flip the guitar over w/o strings, they won't fall out.
Lastly, you sand them to the proper height... either taller, the same, or shorter than your current saddle, depending on how you are trying to adjust the action. The rule here is Go Slow! Sand a bit, check the action, sand a bit more... etc. For that reason, I usually did this with old strings on, and then changed strings after I had the new saddle to the desired action.
First one I did took me a while, but after doing a few, I got to where I could install one in about 45'.
Or, if you send Bob your old saddle, he will make a copy for you (you can specify about how much taller/shorter you want it)...