Jean-Marc Both saws you have selected are of great quality no doubt, personally I cant speak of experience with either but following the great reviews from other members in the village. I have a 788 myself and know its quite capable of cutting those crosses you want to cut. As a matter of fact I'm quite confidant that it will cut anything its a matter of, can you? I often hear oh that's easy for you cause you have a great saw, all the while I was cutting stuff like I am now with an old delta shopmaster I nicknamed shaky. So besides the saw you'll need a ton of patients a good wood selection and I think good blades would be an option.
I look forward to seeing this cross done please post a picture for us to see. Thanks and the best of luck it sounds like you have the bug my friend.
.../Hans