If you're talking Kikuyu or entire GEMA - of course Luhyas are no match - that is why Ruto has extended his campaign to Coast/Ukambani/Matusa - where he is doing far better than Uhuru did.
In Luhya where Uhuru scored 4% in 2013 - Ruto worked very hard btw 2013-2017 - to see fortunes improve to 15% - this time round he is taking to 50% plus.
Luhyas are in 5 counties of western+Tranzoia - majority - and minority in Nandi, UasinGishu, Nakuru, Nairobi and Mombasa. Ruto will benefit from those too.
The same story in Coast - Uhuru was struggling to get 10% - Ruto helped again moved it - 15-20% by incessant campaigns - and now he is going to get 50% plus.
Go to random places like Turkana, West Pokot, Bomet (: - Isaac is in), Narok (Mau sorted) - and Ruto will improve.
Go to Ukambani - Ruto is set to improve significantly from Uhuru 10% - he has Muthamas and Mutuas - plus strong ground team with UDA the 2nd favourite camp.
In Short KIkuyu as much as it give you a boost is also an abastross because Kikuyus or kenyattas are hated in many places like RV and Coast - due to land issues.
This is why you're hopeless against Ruto because as you concentrate on Mt kenya - Ruto is out there running rings around Raila - and the problem most of kikuyus are insular - thinking kenya starts and ends in Kiambu

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You will wake up after putting all effort to get 20% in Mt kenya to hate Ruto to find the entire country rallied behind him and he didnt even need GEMA votes
There are more kikuyu counties than luhya counties...like in Nairobi you have 700k Kikuyu voters 900k kikuyu voters in Kiambu...1.6MN before we move to other counties...I don't think Kakamega bungoma vihiga counties can match that...that said there are more kikuyu voters in cosmopolitan areas like kajiado narok uasin ngishu Nakuru than there are luhyas...so comparing kiambu and Kakamega doesn't make sense.