Age, economics, education and socialization
Under 35 are more likely to with ruto. Poor traditional kikuyus who still circumcise women are 90% with ruto. Kids from poor families socialized to hate well to do families are more likely to support ruto.
It is age and social class
There's a big group of Christian extremists supporting uda in Central. These religious bigots are very closeted and will never come out in the open to support ruto
So it is a bit complex. However, the stands are firmed. Raila and ruto have very little juice left to squeeze in Central. Ruto problem now is gachagua loose mouth and gachagua image