Modifications on a 4.5/6 drop

[rubberbandit]

I have a bare frame and am ready to place suspension on my first frame-off restoration. I like the 4.5/6 drop. I have new CPP 2.5" drop spindles and 2" lowered springs ready to install and will be putting 6" springs in the back.

What modifications should i make at this point? Should I C-notch the frame? Should I replace the trailing arm crossmember and/or the trailing arms? I am using the stock control arms and haven't altered them at all. Is this okay?

I have done searches on these and would like to know what you guys would do or have done and why? Is there something you wish you would have done? I just want to do it one time and do it right but don't want to spend a ton on unneccessary modifications.

Thanks for your help