120g reef tank access recommendations

Good evening all.. I am looking for some advice as to what parts I would need and sizes. I am a newbie to the saltwater tank world and am looking for direction. I currently just purchased a 120 gallon dual rear overflow Aqueon tank. I am looking at purchasing the JNS Cones c0-2 skimmer and the Eheim 1262 return pump (will that give me enough for my dual overflows? which are rated at 600 GPH) and the Reef Breeders Photon 48 LED (canopy mount) and wanted to get everyones thoughts on these. I am also looking to find out what size sump you guys would recommend. I am building my own stand at approx 38-40" tall so I will have room for the skimmer and other items. i'm just not sure as to what size sump ?? 20?? 30?? 40?? Anyone have any particular brands to buy or just build one? If I were to build it, what would I need and how would I set it up? Also, I have been looking at purchasing 2 of the Jeboa RW-8 Wavemakers (thoughts would be greatly appreciated). Which heaters should I get?? I read that 2 heaters are better than 1. At the present moment my tank is empty and I am piecing everything together. I have been doing a lot of reading and do not want to buy things twice. I know I would need live rock to start the tank cycling process faster but what else would you recommend? So any information and thoughts regarding the items I am looking to buy would be greatly appreciated. Thanks very much for taking the time.