L.W.
personally I say go for it but still do diapers at night and nap. I did the 3 day potty training for my daughter when she was 20(ish) months old. If you look at "my questions" on my bio you can see that I asked about the 3 day potty training thing awhile ago
Did it work YES...but not without accidents. It was a great platform. I STILL put my LO in diapers at night time....She was fully potty trained (on both) by 2 years and 2 months (26 months old) but I only stopped diapers at nap time about a month ago (well daycare did it for me)
Good luck..but dont sweat it....keep the diapers on when he is sleeping.