You've got a lot you are asking about.
1. The Pioneer receiver is extremely outdated and is not very good. It's entry level and incapable of biamping.
2. Bi-wiring is typically called BUY wiring. It's a waste of money and produces absolutely no audible difference, period.
3. Bi-amping can be good if you have really good speakers, and good amplifiers which can discretely power the separate sections of the speakers and you will be playing them at volumes which will drive the amplifiers hard.
4. Generally, you want to go with 14 or 12 gauge cabling, not 16 gauge, except for VERY short runs. You can pick up inexpensive 12 gague cabling at
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5. The Radiient speakers seem to be of solid mid-level quality and should be fine. Bi-amping them at some point may make sense with the appropriate setup.
6. I would hope you are not running your Klispch speakers at the same time you are running the Radiients. Typically, this is not condusive to good sound, but you seem to like what you are hearing, so it's your ears on this one.