Ashman,
use the 20-50 and make sure you use a high quality oil - I recommend Castrol. If you change it often enough you do not need to worry about the synthetic. I know that when I changed it at 3k then there WAS NO SLUDGE to drain out overnight. Change it hot and change it often and you will be fine. I would not go the synthetic route.
engatwork
'95 E320
'97 Honda CRV