At 350° in an oven, you would cook whole pork approx. 25 min/lb. to 160° internal. At 230° you would lengthen that to probably about 45 min. a lb. But, that's not accounting for stall or if you've pickled it first, which might alter cooking times. The key figure here is to 160° internal, however long it takes to get the thermometer to read that in several areas of the center of the ham; could be 10 hours, could be 15 hours or anywhere in between. Regardless, I'd do it on Saturday so you've got plenty of time; if you're off that day start it early and you will be able to get a good night's sleep (and if not, have a 6 pack handy!).