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.
Parasound 5125, Parasound 2100, Pro-ject RM 5.1SE, Dynavector 10x5, Pro-ject Phono Box S, Pro-ject Speed Box II, Arcam FMJ CD17, Pioneer Elite VSX-52, Pioneer Elite BDP-52FD, Vienna Acoustics Bach Grands, Vienna Acoustics Theatro Grand, Wharfedale Diamond 9.2s, REL T-1 & Panasonic TC-P54S1