I'm aware the tank has no fish in it yet

. The thing is, bacteria are sensitive to shifts in temperature. If you cycle at 86 you'll get bacteria that like 86 degrees and then you'll kill them off and have another cycle when you lower the temperature. Granted you won't kill them all off, but you won't have a full load of BB when you start to add fish and will get ammonia spikes and mini cycles. You're much better off cycling the tank at the temperature you want for the fish you're going to get. Regardless of temperature cycling will take as long as it does. For some people its a 4-6 weeks, less sometimes if you get a seeded filter. For others its 3 to 4 months and I have some friends who were trying to cycle a tank for 8 months and just gave up and did a fish in cycle.