Python 2, 156 bytes
r=('AaBbCc.BbCcDd.EeFfGg.HhIiJj.KkLlMm.NnOoPp.QqRrSs.TtUuVv. WwXx.%8cy.%10c.%10c'%(89,90,'z')).split('.')
for k in r+r[-2::-1]:s='%-10s'%k;print s+s[::-1]
Maybe the formula 512/(i**4+47)-1 is of interest to future golfers: it maps the integers around 0 to $$\cdots,-1,-1,0,3,7,9,\fbox{9},9,7,3,0,-1,-1,\cdots$$
which encodes how many spaces to prepend to each line ((-1)*' ' being equal to 0*' ').
Python 2, 156 bytes
r=('AaBbCc.BbCcDd.EeFfGg.HhIiJj.KkLlMm.NnOoPp.QqRrSs.TtUuVv. WwXx.%8cy.%10c.%10c'%(89,90,'z')).split('.')
for k in r+r[-2::-1]:s='%-10s'%k;print s+s[::-1]
Python 2, 156 bytes
r=('AaBbCc.BbCcDd.EeFfGg.HhIiJj.KkLlMm.NnOoPp.QqRrSs.TtUuVv. WwXx.%8cy.%10c.%10c'%(89,90,'z')).split('.')
for k in r+r[-2::-1]:s='%-10s'%k;print s+s[::-1]
Maybe the formula 512/(i**4+47)-1 is of interest to future golfers: it maps the integers around 0 to $$\cdots,-1,-1,0,3,7,9,\fbox{9},9,7,3,0,-1,-1,\cdots$$
which encodes how many spaces to prepend to each line ((-1)*' ' being equal to 0*' ').
Python 2, 161156 bytes
r='cCbBaAr=('AaBbCc.dDcCbBBbCcDd.gGfFeEEeFfGg.jJiIhHHhIiJj.mMlLkKKkLlMm.pPoOnNNnOoPp.sSrRqQQqRrSs.vVuUtTTtUuVv.xXwW WwXx.yY %8cy.Z %10c.z '%10c'%(89,90,'z')).split('.')
r+=r[-2::-1]
for k in rr+r[-2:s='%10s'%k;print:-1]:s='%-10s'%k;print s[s+s[::-1]+s1]
Python 2, 161 bytes
r='cCbBaA.dDcCbB.gGfFeE.jJiIhH.mMlLkK.pPoOnN.sSrRqQ.vVuUtT.xXwW .yY .Z .z '.split('.')
r+=r[-2::-1]
for k in r:s='%10s'%k;print s[::-1]+s
Python 2, 156 bytes
r=('AaBbCc.BbCcDd.EeFfGg.HhIiJj.KkLlMm.NnOoPp.QqRrSs.TtUuVv. WwXx.%8cy.%10c.%10c'%(89,90,'z')).split('.')
for k in r+r[-2::-1]:s='%-10s'%k;print s+s[::-1]
Python 2, 162161 bytes
r='AaBbCcr='cCbBaA.BbCcDddDcCbB.EeFfGggGfFeE.HhIiJjjJiIhH.KkLlMmmMlLkK.NnOoPppPoOnN.QqRrSssSrRqQ.TtUuVvvVuUtT.xXwW WwXx.yY Yy.Z Z.z z''.split('.')
r+=r[-2::-1]
for k in r:print'%-10s%%10s'%k%k[s='%10s'%k;print s[::-1]1]+s
Python 2, 162 bytes
r='AaBbCc.BbCcDd.EeFfGg.HhIiJj.KkLlMm.NnOoPp.QqRrSs.TtUuVv. WwXx. Yy. Z. z'.split('.')
r+=r[-2::-1]
for k in r:print'%-10s%%10s'%k%k[::-1]
Python 2, 161 bytes
r='cCbBaA.dDcCbB.gGfFeE.jJiIhH.mMlLkK.pPoOnN.sSrRqQ.vVuUtT.xXwW .yY .Z .z '.split('.')
r+=r[-2::-1]
for k in r:s='%10s'%k;print s[::-1]+s