rb25det idling question

[240s-sex]

i have my s1 rb25det that i finally got idling, smooth but idk what the idle is supposed to be at

i know its kind of a strech but does anyone know what the proper idle would read on my 4 cyl stockl tach

i kno its gettin the wrong signal from the 6 cyl i was just wondering if maybe someone had an SAFC set up or something to read rpms and could give me the rb reading and the stock tach reading

thanks