Using one pair two sets of wires for each channel

Dear Sir,

I just finnished composing my bedroom system with:

Audio Refinement Complete Int.Amp.
Usher CD100
Kimber PBJ
Wharfedale Emerald 99
Homemade Speaker cable (13gauge - not terminated)

The amplifier only has one pair of speaker out while the speaker binding posts are bi-wireable (i.e., two pair of binding posts) - With the given configurations, I am trying to bi-wire my system via applying two sets of speaker cables to each channel. As suggested, the amp has only one pair of speaker out so I have to put two sets of speaker cables to one binding post on the amp.

If I am to use two sets of wires for each channel:

a) Is it safe for my amp or speakers (since the wire becomes too thick [13gauge + 13gauge = ... thick!)?
b) Does it improve sonically or degrade it?

Any comment welcome
Electrically, there will be no problem. Sonically, you will have to decide.
Take a look at

He advocates what he calls "Vertical Bi-Wiring" - Two pairs of speaker cables are attached to the left speaker out from your amp - both are connected to the binding posts on the left speaker

do the same for the right

I'm going to give it a try this weekend -

Read the info on the website and see if it seems like something you'd like to try - the website says that this type of Bi-Wiring provides a remarkable difference (my words)
Thank you Swampwalker - One cannot be too careful regarding audio setup, esp. one in a bedroom; it's got to perform properly when it needs to.
Thank you Pkemery for usuful information above!
Sorry everyone - I was standing in the shower this morning and thought "Holy Cow, how could I have been so wrong" - the vertical bi-amping works by taking two leads from the left PRE-amp out to the to input connections on an amp that will serve just the left speaker - then the two output connections of the amp are connected to the binding posts of the left speaker esentially you have one amp for each speaker instead of one amp serving the woofer of each and another amp for the mid-range or tweeter

I can't believe I left out the Pre-amp part in my original post - I guess I was just too excited about being to offer some input to someone

I biwired for years, simply because there were two sets of speaker terminals available on my ProAc Response 2s and 3s. Found to my chagrin that single-wiring, using Mapleshade jumpers, sounded noticeably better and cost less. But YMMV.