I bet you soon think I will say anything to make you convert the broken boat into an F16

Sure you can sail with the unmodified A-cat rig. If you have a higher mast and higher aspect ratio than the F16s, you will be more prone to cartwheeling. Have a look at Florians excellent model here to get a quick introduction to the differences. http://www.diversediverse.com/rolf/florin/Prosjekt-hard-milk/hard_milk.html (you can rotate and zoom the model)
You boat will not qualify as an F16 until it measures in though, as I am certain you already understand. When the day comes, you can get a new mast or rebuild the one you have. Put on a new mainsail and be going as an F16. I would not drop the spi though!

Anyway, it would be a shame to let what is a mostly complete boat dwindle away when you can put new hulls on and sail it instead.