B2500 diesel

So i have a 97 b2500 diesel cab+

I have to repair some rust in the frame right behind the cap and i want to z frame at the same time...
My wheels are 8,5x18 with a +40 offset and 245/45-18 tires, and i want to just static drop it for now!!

How much should i z it ?? 2" ? 4"? any??

Do you plan on baggin in the future? Keep in mind if you z the frame in the rear you will have to cut the bed floor and move it up to drop the sides of the bed down to keep it in line with the cab and body line. By the way love the front end we don't have that front end here in the states.

It's illegal where i live to bag cars whitout a special and very expencive test... but i think i'm gonna do it somtimes i the future...

I know about the bedfloor, but that's not a problem... i just wanna know how much i have to z the frame...

Would a 3" z be ok with my wheel size ? anyone ?? Help

Check out this guys project I know he z'ed his frame but not sure how much. Might be able to read throught it and find out or pm him and ask.