I need to replace the leaf springs on my 29 U. Looking for advice.

I used these guys to replace the springs on my car. 

https://www.eatondetroitspring.com/

Contact:  Gary
EATON Detroit Spring, Inc.
Phone 1-313-963-3839
Fax     1-313-963-7047
gary@eatonsprings.com

If your springs have the helper springs they do not make the helper spring but will mount your original helper springs on the new leaf springs.

My old front spring:


New front spring:

Thanks Gary

They made one for me too and I was very pleased.  I made one missing helper spring up myself.