Over time i've found the 2* per 50 hit does'nt always work , in saying that it worked pretty well on an old 440 i ran , the 605" i run now likes around 1* per 50 hit (300 shot) if you base it on timing pulled per 50 shot , when i sprayed it with a 200 shot it liked 1.5* per 50 , so you can see with this engine the more i spray the less spark lead needs to be pulled , if i step up to a 500 shot then who knows , it might start going the other way regards timing , guys new to this have got to start somewhere & i found the 2* per 50 WAS a good starting point when i running the cheater plate , if the fuel you use is the correct rating & the plugs are right for the ammount of spray you're gomnna be using then i don't think pulling 2* per 50 is gonna hurt the motor when spraying around 150/200 shot , just gotta read those plugs after the first 1/8th make pass & go from there , you may find the motor wants more or less timing , @ least you had a starting point ,& yes bigger hits are a different ball game , but by that time the begginer should have a hadle on it.