14/2 vs. 14/4 cable, would I notice any difference at this length?

My B&W CM1s will be powered by a Denon 2809CI. I need to decide between running 14/4 wire (combine two pairs, to make an effective thicker gauge) vs. running 14/2 wire.

A local expert told me to disconnect the metal bridge between the mid and tweeter on the CM1s and use 14/4 even though the pairs come together at the amp. But then everywhere on the forums I read everyone just uses 14/2 in similar setups.

At a length of 30 to 40 feet for the furthest speakers, would the different cable effective gauge make any discernible difference at all?

I found the following anonymous comment on a product review blog. I am leaning toward bi-wiring the CM1s while removing the speaker jumpers. While this post offers good clarification about terminology, I am not sure why this says that removing the jumper would result in eliminating the low end. I think that's without basis, and incorrect. Thoughts?

"Bi-wiring is sending 2 sets of wires to your speakers with from the same output without removing the jumpers on the speakers. Bi-amping is sending one set of wires from one output to the high side connection on your speakers and sending a second set of wires from a different output (that is the same as the front speakeer output) to the low end connection on your speakers with the jumpers REMOVED. If you bi-amp without removing the jumpers you can destroy your speakers, and if you bi-wire and remove the jumper you are eliminating the low end of you speakers. Bi-amping has a benefit, bi-wiring has none."

The B&W manual directly contradicts the above poster about the low end:

"For bi-wire connection the terminal links should be removed and each pair of terminals connected to the amplifier independently. Bi-wiring can improve the resolution of low-frequency detail. Figures 2a and 2b illustrate conventional and bi-wire connection."

A different poster writes:

"One improvement is the removal of the jumper connections between speaker binding posts. In my experience, these are usually cheap stamped brass plates with a shiny coat of gold. Even the simple act of replacing these with a length of good 16 gauge OFC solid-core wire can make an audible upgrade. Losing this connection altogether with bi-wiring is even better. Bi-wiring also provides separate return paths for the speaker's woofer and tweeter, reducing the quantity and effects of back EMF in each cable. 'Keeping the pathway clearer' so to speak."

And then another interesting comment:

"The reason bi-wiring improves sound has to do with the crossovers inside the speakers. Passive crossovers are basically resistors that block out certain frequency ranges. With a bi-wired setup you are putting more distance between those crossovers in the circuit, which, to say it plainly, lets them do their jobs with less interference from each other."