Congrats on the Diamond 10.2's. The RCA stuff is CCA, Copper Clad Aluminum, and personally I would not use it, even for short runs. So is the GE Pro wire found at Home Depot, Lowes, Targets, etc. Speaker wire doesn't have to be expensive but it should at least be pure copper.
Even with shipping charges, I still suggest Monoprice because it is quality pure copper wire at a good price. But if you cannot wait for Monoprice because you will have your speakers in two days, I would suggest the Rocketfish 16 gauge wire at Best Buy. It is pure copper and I believe it comes in 30 foot spools. Should be about the same price as Monoprice wire plus the shipping charge. Good luck.
Marantz PM15S2 LE, Oppo BDP-103, Simaudio Moon 100D DAC
VPI Traveler V2 with an Ortofon Rondo Blue and Simaudio Moon 110LP, Technics SL-1400 with an Audio Technica AT-14sa and Pro-ject Phono Box S
Dynaudio Focus 260's, Rel T-1 and a Panasonic TC-P54S1.