I used Pansage/Simisear right the way through my white run. I also spent ages in Pinwheel forest hunting down the other two, but they never made it onto the main team. All three are at level 100 now though.
For anyone interested, by friend code is 5257-9947-2315. If anyone wants to add me, remember to PM me so I can add you too.
My friend safari contains the ground type pokemon Phanpy, Marowak and Palpitoad.
Current Y team consists of Delphox, Pidgeot, Raichu, Simipour, Charizard and Gogoat.
In training: Wartortle, Bulbasaur, Chespin, Froakie, Combusken, Pangoro.