Judging from the latest post [170427 MMDigest], Ronsen hammers win.
The Wurzen felt is the preferred hammer on some piano tech forums
because they sound like old time Steinway hammers right out of the
box.  I think they are sold as Ronsen Weickert hammers.  Very nice.

Ronsen will weight match to your samples.  Erwin's Piano Restoration
in Modesto, California, also sells a version of this hammer and can
bore them plus mount them on shanks ready to install.  PianoTek also
has this service.

The new hammer butts and flanges from Japan are not correctly sized
for a lot of old upright pianos.  They are a "one size fits all" part.
In particular, they are wrong for Coinola, Seeburg, and Wurlitzer
coin pianos.  If you have wood flanges then the new ones are two
loose on the action rail and will move with seasonal weather changes.
The butts have a catcher that is fine for spinets but not old uprights.
The hole for the hammer shank is at an improper angle causing the
hammer to strike the string at the wrong angle.

It is better to replace the felt and leather with new materials.
I believe the leather substitute is known as Ecsaine.

There is mixed opinions about the grand piano action parts from Japan.
Some techs say they like them while some will use only Renner.

Don Teach
Shreveport, Louisiana