I am in the process of installing an in-ceiing 5.1 HT system. I have 4 SpeakerCraft in-ceiling 7" Aim7 Two speakers and a 8" Aim8 Three for the center channel. Is this a better setup than using all (5) Aim7 Two speakers? I cannot afford to buy all Aim8 speakers, since they cost twice as much as the Aim7s. The speakers will be driven by a Yahama RX-A1010 Receiver. Thanks.