Drop BLock Question

[69C10@16]

Ok. I want to drop my truck either 2/2, 2/3, or 2/4. I havent decided yet. But, I have found 2" drop blocks for sale in various places. Would it be safe to say that 2" is as big as you want to go with blocks?? I thought about getting some kind of I-Beam set up or taking some thick flat-stock and cutting it to make shims. Like the drawing below. I figured if i welded the shims together it would be MORE than strong enough. Im trying to keep from replacing the coils because before i realized i wanted to drop it i replaced them with 3/4 ton springs. Stupid me right? the old ones were in BAD shape anyways. So do you think if i get some really good u bolts I could pull it off. that is, pull it off SAFELY? Any info and opinions would be GREAT. THANKS!