The best seems to replace 7B by FB at 422Fh and F0 E0 04 by F8 F8 04 at 423Bh.
Hi gdx, the data F8 F8 04 at 423Bh are not perfect on the tail...
The standby and running frames are shared !!
Seeing that the right position is ok, I think you can compare all the sprite positions and fix it:
4200h (01h 03h 00h 00h ...) for to the LEFT
4600h (00h 01h 1Eh 0Ch ...) for to the RIGHT
Do you see the symmetry in the first 16 bytes?
As the sprite is like this:
OK, the problem is the foot is too long a pixel and the wing which exceeds
the frame you indicated is shared to this:
the tail will be partially empty if you use F8 F8 04
yep, you are right ... sure that in this game all the sprites are in very bad conditions! 
I'm sorry I think the foot is not ok yet (tested at 50% of speed with blueMSX).
I go to sleep now! 
This time I took the time to make screenshots to compare. We had confused two sprites. The first modification was good although incomplete. So there is little data to change. If we replace sprites data as below:
7B by FB at 422Fh
F0 E0 04 by F8 F8 06 at 423Bh
We get this:
I can get proper screenshots as your but it's enough to see that it looks ok now.