Is it practical to solder an SMD component directly over through-holes if the pad pitch matches? What are the usual methods for preventing solder from wicking into the holes and ensuring a reliable solder joint?
For a one-off DIY project, I wouldn’t be too concerned if the pad pitch matches and you can get a good solder joint. The situation changes for production, where solder wicking and assembly defects become much more important to control.
I’d also consider what the SMD component is doing. If it’s a power device that needs an exposed pad or nearby copper for thermal management, the through-holes underneath become a much bigger concern, as solder will wick away and ruin the thermal/mechanical connection. As for preventing wicking in general, the usual methods are ensuring the holes are tented with solder mask or filled with epoxy.