Help With OHMS, Speakers, Reciever

Hello Everyone,
i need some help with setting up the speakers and amplifier/reciever.

Don't know who to contact.. people at the store don't know these technical terms and denon.ca wasn't any help.

Here's the situation.
i've been using Logitech z5500 speakers for 15+years now....
recently decided to upgrade the whole entertainment section.
and decided to go buy a new receiver as well but will wait about a year for the speakers because don't have proper space/setup for the speakers.

Currently deciding to use the z5500 sattelite speakers as i have 3 sets of 5 speakers

i'll only be using 5.1 setup because of the space...
have the seperate sub-woofer , wont be using the z5500 one.

here are the Specs of speakers .(according to internet)
Left/Right: 62 watts RMS x 2 (into 8 ohms, @ 1khz, @ 10% THD)
Center: 69 watts RMS (into 8 ohms, @ 1kHz, @ 10% THD)
Rear Left & Right: 62 watts RMS x 2 (into 8 ohms, @ 1kHz, @ 10% THD)

Here's the specs of Denon S960H :
- 90W per channel (8 ohms, 20Hz-20kHz, THD: 0.08%, 2 channel driven.
- receiver can handle 4-16Ohms
- Doesn't support Bi-amping.

My question is :

-since i have so many sattelite speakers laying around.... Can i connect two speakers to each channel.
- which would be better Parallel or Series
- if its too much power can i connect atleast center channel x2 .,. since i'm sitting 20ft from the center channel and right underneath the back speakers



i know i can change the level of the speakers to be less loud and more loud.but i would prefer connecting more speakers...
i know i can connect it and they will work ... either in parallel or series but i want to make sure i don't want to blow up anything specially the receiver ...speakers are ok because i'll eventually change them... :-D

Please if someone can help me on this topic. who have an idea about Speakers, amps and all the other things.

Thanks for taking your time to read and reply.
DjSingh.