The 1640 is superior to the 1650 -- it scans better, it reads better, and it burns better, IMHO.
I prefer BSMB for the 1640... BSLB is a close second for me.
I would disable solidburn and WOPC on high quality media, like MCC 004 and Yuden. For everything else, I would use WOPC. I would use solidburn on batches of discs that don't burn well with it off. I would try with it off first, then move to having it on to see if it is improved. Often, I will clear out solidburn after just 1 burn, too.
Again, I'm sure everyone has their own methods.