Pardon my noobitude here. I am getting to the end of my first woodwhisperer inspired endgrain cutting board and due to some rookie 'learning experiences' (i did not have the board as flat as i thought it was before making final cuts, lesson learned) the final glue up has left the strips at uneven heights. If this wasn't endgrain I was working with, I would get it flat with a block plane (no access to power jointer or planer), but I don't really see that as an option with endgrain. I have a couple RO sanders and a belt sander at my disposal, but I'm concerned that by using these it will be difficult to get the board really flat.

Is it worth trying to find someone in the area (north of Seattle) that may be willing to let me use their drum sander, or should I be able to achieve similar results with a belt sander and some finesse?

If there are other options for making this board flat that I am completely overlooking, I would love to hear about them as well. Thanks for reading.