STRUT CASING HELP!!!

[Akuma Dori]

okay ive done a few research but its confusing me still having different write up's and do's and dont's...

well i want to convert my front suspension into a coilover set up.. what i have? are the following parts:

paradise coilover kit with 8kg spring
tein camber plate
battle version nrca's
front kyb agx 4 way adjustable

now i would like to be sure how much do i really have to cut off my struts?

someone says cut it 60mm and put 20mm of spacers...
someone says cut it 50mm and put enouch spacers to lock it down
someone says cut it 40mm and put enough spacers to lock it down
.....

well heres another future plan, i am only using this shocks because my trd shocks wont be available until next month (coming from japan) so what i would like down the line is that i want to make sure when i cut my struts i would still be able to use the trd shocks without recutting my struts again..

i would really appreciate all the help, opinions and suggestions.. thank you!