When it comes to press dies, just use A36 hot roll. Anything else is just wasting money. Why? Anything that requires hardening/tempering.... the heat will quickly "draw" the temper of any hardenable material to dead soft in short order when used as press dies.
I learned this the hard way.... I purchased enough D2 for a set of flat, and a set of combo dies for my press (big bucks)..... took the time and effort to heat treat, and install them.....only to have them "temper out" and start to deform they're first day of use. After stomping and fussing like a little kid, it finally hit me....DUH!
Just purchase the size materials you need in A36 (I purchase 3/4 or 1" thick X whatever I need), cut to length and tack weld them to your die holders.....when the dies get too deformed.....just grind the tack weld away, and replace the die.