There is a way around this. Although Charpad V2 is not compatible with the sideways scrolling SEUCK editor. It is possible to use Charpad for Sideways SEUCK. You would need to do things in a different way.
1. Set tiles as 5x5, map as 8x512 which the standard SEUCK uses.
2. Draw your tiles. After drawing them, compress your tiles and ensure 254 characters are available on screen. Also make sure you have 128 tiles.
3. When happy with your tiles and completed step 2, go to file / import/export / SEUCK / Export background data file
4. Load in Charpad V1.8 and go to file / SEUCK / load background file. Once the SEUCK background data file has loaded, you will be asked if the graphics for the Sideways SEUCK mod.
Click on "yes" and then start plotting your tiles onto the map.
5. Finally in order to load it into Sideways SEUCK, go to file / SEUCK / save background file. Then of course import the saved background file into your D64 image, load up SEUCK and then load in the background file and have fun with the rest of your game development project.