...bear in mind that one thing is get rid of the crust and follows the blanks curvatures other is to shaping a blank. The planer is the tool for shaping blanks not only roughing, you shape all with the planer except some details or too flipped shortboard noses etc where you finish with the surform or sander. Even flat channels are done with the planer; only concave channel like bonzer you do (the main ones) about 40% with the planer.
Yes, you can do with hand blocks and sandpaper but try to not to do a "spot" sanding always long passes. The curved surfaces are in the need of X pattern sanding then long ones from the other side of the racks.
Here’s Matt showing how he makes the rail scribe tool out of a scrap of foam. I’d have a look at his other vids on YT as well.