Help/advice with new system BAT VK-500/ B&W 801 S2

I would very much appreciate any advice or assistance with some questions I have in regards to my "new" audio system.
I am moving up from an older Rotel system I have had for over 18 years.
I recently purchased:
Balanced Audio Technology VK-500 (250 amp/channel @ 8 OHMS)
Pair of B&W 801's Series 2 speakers.
Wireworld Silver Electra power chords (BAT amp requires two)

Since I am on a budget, I have to remain using some of my old Rotel components. I plan on using my Rotel pre amp (RC 9908R) (RCA outputs/unbalanced). I also plan on using my Rotel CD player.
Within the next 3-6 months I would like to upgrade the pre-amp from my Rotel to a balanced BAT VK-30 SE unit.

In the meantime, I have a few questions:
1. Since I have my Rotel amplifier from my old system available, should I bi-amp my 801's vs. using only the BAT VK-500 amplifier solo? The Rotel amplifier (RB 980 BX, 120 watt) is still in exceptional condition and drove my older B&W (DM620) very well.
2. Since my system (using my existing Rotel Preamp) will be unbalanced and using RCA's, how much will this affect my "new" systems sound quality?
3. I still need to purchase new speaker cables. Can someone propose cables for my BAT amp? I also need to stay within my budget of $500.00 or less for the pair. I need to first determine if my system is better set-up in bi-amp mode or run my single BAT amp - then I can start looking for the correct speaker cables (bi-wire cables or single speaker cables etc..).
What is the minimum wire gauge that should be used for an amplifier of this size? Since there is such a large variety of manufacturers (and price variation), someone new trying to define their cabling needs is very confusing. It seems like every cable manufacture's product review is "exceptional" etc.. I am concerned I won't purchase what I need to build my system correctly!

Last question - I have seen people put their B&W 801's on stands. Is this a must or determined by the set-up of the room? My listening room is 25'W x 30'L.
Again, any help would be very much appreciated. Any input/ advice about any of the items I have discussed will only help me further my audiophile education.