I don't have any actual number suggestions for this, I'm mostly going to be arguing purely from a relativist point of view with hives and kennels.
T2 Kennels:
cost: 550 mass, 2750 e
gain: 25 BP
22 m per BP
110 e per BP
T3 Kennels:
cost: 500 mass, 2500 e
gain: 25 BP
20 m per BP
100 e per BP
Hive:
cost: 350 mass, 1750 e
gain: 25 BP
14 m per BP
70 e per BP
Kennel Average:
21 m per BP
105 e per BP
Hive Average:
14 m per BP
70 e per BP
Hive is the same as all tiers of hive are the same efficiency.
So you can spend 1050 mass on a kennel to give you 50 BP or you can spent 1050 mass on a hive to get 75 BP, the e cost is pretty much the same too.
"A kennel gets infinite range tho" Ok but this isn't really a benefit. Hives are able to switch targets to anything in their range instantly and that can basically cover everything they need with a remotely planned base. Nuke, SMD, Gateway, Air factory, and shield to protect itself. Drones need to waste travel time moving from one to another.
Beyond that, drones are interactable with the environment and can be shot down. This means the "epic sick OP" thing of using them to help with forward bases or getting reclaim isn't even a real thing since they can instantly die and take forever to rebuild.
SPEAKING OF THAT, if they get transferred to new people, the drones die and need to get rebuilt. Hives don't.
Also, recently found this out with farm, when you lose a max upgraded hive, you get full reclaim value back for the cost of all 3 sum hives. For kennels, you only get the cost of 1 upgrade, which for t3 kennel is the cheaper of the two. You only get 400 mass for reclaim. It's literally the worst thing possible in that situation.
I'm going to be generous and say that the drone mobility is a net neutral thing AND THAT'S BEING REALLY GENEROUS. In that case, kennel and hive should be at least totally identical in mass efficiency. If you take the VERY REASONABLE take that hives have massive utility with insta-transfer of bp, then you should swap the mass efficiency of kennels and hives.