Currently got an angleset on my bike, ZS49 upper EC49 lower, for tapered steerer fork. The headset, bought used, came with 1 lower EC cup (0 degree) and a series of upper cups.

I am about to put an older fork with a straight steerer back on. I could use a converter crown race, but I am wondering if it would be stiffer if I use a ZS49/30 lower (already have the cup and a spare bearing so all I’d need is a 30mm gimbal and crown race).

My questions are:
1 For a straight steerer is there any real benefit in a ZS49/ZS49 setup against just using a converter crown race?
2 For a ZS49 upper ZS49 lower with an Angleset do I just put a zero degree cup at the bottom, same as with the ZS49/EC49 I have at the moment ?

thx