I know nothing of either of the forks you mention, but I'm doubtful any fork, in any material, that's designed for disc brakes and front rack is going to have much give in it, though that's mitigated by larger tyres of course.
When I was searching for something similar a few years ago, Vicious Cycles in the US kept coming up with plenty of praise, in the end I went with something cheaper from IRD, though they seem to have dropped their steel range. If the length/offset works for your new frame, the SOMA Wolverine fork might work, though it's no lightweight.