I found out that ugridstoload is working if you enter it in general section of skyrim.ini.

I haven′t recognized any issues besides memory usage getting to high, so skyrim crashs. But crashs can be prevented by regularly entering pcb as console command. By doing so I walked several minutes in Skyrim around without any crash. I used ugridstoload=11.

Maybe a mod that run the command every xx seconds or by entering a new cell, will let ugridstoload be a usefull ini entry.