Is there any difference between the progressive drop in kit and the regular lowering kit?

I put 11" progressive 412 shocks in the rear and want to level out the front. I plan on disassembling the front end over the next winter to powdercoat. I am also going to replace the 19" front wheel with a 21".

So basically 2 questions... Drop in or standard lowering kit and with the 21" wheel, how much do I lower the front to even things out.

Thanks.

 

If I remember right the 21" tire puts the axle about 3/8" higher from the ground.
I put the standard kit in mine and it lower my bike with the 1" spring under the damper tube/pipe lowered it 1 1/4".

 

I put Progressive 11 in. on my SB and Progressive drop in in front, it was easy to do and it works like a dream, i think 1 in. all around would be just fine even with 21 in. wheel.