Are Squats worth 3kg of quad mass??

Deadlift would kill your nervous system Period! At my first university year, i was doing 500pd deadlift after speed totally crap idea.

Maintain the squat, but with much lower volume.

Exemple:

Mid season
Squat 2x6
Romanian deadlift 3x6
Leg curl 3x8

Advanced
Power Cleans 3x5
squat 2x5
GHR 3x6-8

Drop some hamstrings volume as top speed volume increase. Uphill GPP would be the best time to crank-up the volume for hamstring work.