I used 3rd gen emu springs because I allready had them. I ended up with shackle hangers on the bottom of the frame rail. It works and flexes great. The shorter spings are just fine but if you are starting from scratch and you have them you might as well use them. I didn't mount the hanger way out front, just in the typical location. My front end is maybe 1.5" further forward than most RUFs.
I have tuned the leaf packs over the years and I ended up with the top 3 leaves from the 3rd gen emu, the bottom 2 from a stock front pack and a short cut overload on the bottom of it all. I have found that everything feels healthier and handles better if you shoot for more leaf material in the rear of the leaf pack, kind of mimicking the old stock front leaf packs. There must be some engineering reason for the way they built those springs on stock solid axle Toyotas.
Lately I shortended my shackle length about 2" and it really helped with handling and actually flexes even better for some unexplained reason.