I have been playing with the Eld-x in 178 and 200 gr .30 cal. The bullets are showing up here a couple boxes at a time and are hard to get. I had one box of 178's I worked up a couple loads for my 1903 sporterized Springfield, 30-06. They were shooting less than 3/4" at 100 but I ran out as I was loading for 3 different guns. I finally got hold of a couple boxes of the 200's and worked up a load for them in the two 30-06's I use for hunting. One is the Springfield, the other a newer Rem. 700 LR. 55 gr H4831, cci 200 primers, RP cases. Loads for both guns were set at .02 off the lands for best results. 53-54 grs didn't hold as tight as the 55 gr and I haven't gone above that. 5/8 in groups in both guns with the same load but different seating depth. The Springfield has a short throat, the 700's have loooooooooooong ones.
I think the Eld-x's are as good or better than the Amax and probably a lot better if you are driving them at the higher velocities. I keep mine under 2700, usually 2400 to 2600 and under 200 yards.
I will be working up a load for a Ruger Precision in .308 soon but will have to snag some more 178's first. I have had them on back order at Cabela's for 2 1/2 months.
As far as load data, you can go to the Hornady sight and they have all the loads for the Eld-x's listed that they have tried. Just do a google on Eld-x load data and go to that site. There isn't a lot yet but they do have the 30-06, 300 win mag and others. I have also been informed to use A max data in Lou of. Expect to buy some new powders as there aren't a lot of data on the older standbys. I think the RL's are covered along with some of the newer ones.
Good luck