This site is not accurate for boosted (open ESC) setups. Seems fairly accurate for zero timing setups though.
eg. my 17.5 duo3 with tekin RS is geared at 6.0 FDR for super stock racing on a medium sized carpet track. Some guys go as high as 7. Outdoors on a large track I might lower that to 5.8
I'm currently using 48 boost (5xxx-18500 rpm)
12 turbo (Ramp 2, delay 0.02)
2 notches above 0 for endbell timing.