Which Speedo gear.

I've been looking at gearing charts all night and have narrowed my options down to two speedo gears, a 41 tooth and a 43 tooth. Every chart I've looked at has a different option to use. I'm using a BB 727, 4.11:1 gear, 245/40r18 ET streets, and not sure what gear I need. From what I've read the 245 calculates to a 25.7 Diameter tire, and haven't found a chart that has 4.11:1 gear, they show 4.10:1 with either 25" tire or 26". Has anyone figured out the math or could just tell me which gear to purchase?