I hate answering people's questions in VM's. I much prefer using PM's.
I never really hacked the RSE games much, so I've never really needed to look into it. But knowing what I know, to use the Real Time clock, you'll need to know how to use more than variables. Variables will be the least of your troubles if you want to use the RTC.
Command #0x11 (I think it's command #11, I can't remember) is only useful for making small changes. While changing one palette is 16 colours, 15 viewable, all taking up 2 bytes each. To change just one palette, you'll need 30 writebytetooffset's. Then if you want to change the whole 16 palette's viewable in VBA's Palette Viewer, that 256 writebytetooffset's. With the command's structure which takes 6 bytes, I think, that's 1530 bytes (I think, I did that in me head). There is a point to this.
In ASM it takes about eight bytes of coding to fill those 256 colours. ASM is much more efficient. The time it takes for those 256 writebytetooffset's to be executed is substantially greater than the time it takes to go through the 4 thumb instructions.
I got a bit off track. But yes it is possible to perform a pallette change with writebytetooffset's.
That's why I prefer PM's. I write too much.