1970 C20 leaf spring lowering

[Areohbe]

Hey guys,
I am a newbie here. I just picked up a 70 C20 with rears leafs and wanted to know what lowering shackles would work to get me another 2" out of it? I have already taken 2 springs out and it looks good but I would be stoked on a little lower. Where have you guys purchased them?
If I can't use the lowering shacles what about the axle flip? What product have you used that seemed to work best for you?

I also am looking for a stock style bench seat for it if you know of any in Cali.
Thanks guys....