Just get any bolt thru kits you can get and buy your own bolts to your required length to go with it. I got a Thermalright Bolt Thru kit for my Scythe Infinity which didn't go together so well since the backplate bolt holes were a little small for 6-32 bolts. There's also the Scythe bolt thru kit which should be much better. Backplates are easy to find everywhere, just get one that's strong and buy your own bolts.