Is "select cystine" not implemented in Jmol?
How do I get the number of ssbonds? SEE BELOW.
For number of ssbonds, check results with multiple-model files!

3kwb has 6 ssbonds, 4 free cys, and 8 met (no mse)
3juu has 2 ssbonds, 2 free cys, and lots of met (not mse).
5cev has 0 ssbonds.
3fad has a non-amino acid disulfide between beta-mercaptoethanols in the
biological assembly from PISA.
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Jmol 12:

To get number of atoms of a specified kind (this is a JS function, not
a jmol command!):

jmolGetPropertyAsArray("atomList","cys.ca")

jmolGetPropertyAsArray("bondInfo", "cys.sg").length
reports the number of SS bonds! (in 12.0.RC5_dev).

It does not exist in 11.8.22. 12.0.RC4 fails in FirstGlance so I cannot
use it for the initial ssbonds release.

In jmol,
getproperty bondinfo sulfur # works
getproperty bondinfo cys.sg # fails
getproperty bondinfo "cys.sg" # works

To set the ssbond thickness according to the size of the molecule,
use "getproperty boundbox", noting (under "show boundbox" in the docs)
that the X dimension of the box is 2 * Xvector, etc.

for 3kwb
boundbox {26.1935 14.992498 22.418999} {29.7845 30.6855 38.666}
measured dimensions approx 
 x = 36 
 y = 75
 z = 76


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EXISTING in FGiJ 1.44:

SSBondsBBSpt (using colorSSBonds) is in scripts.js and is used in
  makeHideSidechainsSpt() used in makeVineSpt()
  cartoonSpt
	rocketSpt
  rainbowSpt

clearSpt has ssbonds off.

makeVineSpt(), makeWireframeAllSpt() set ssbonds sidechain.

makeContactsViewSpt() in showContactsSticks mode
displays ssbonds at 0.15, sidechain.

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Next: try making Cysteines "found" with halos instead of spacefilled?
Or stars? Or dots?

Test SSBONDS w/ consurf colors.

Make quality button change translucency of backbone if ssbonds mode.
3 for quality; 5 for not quality.

NEW in FGiJ 1.45:

help.js More Views calls doSSBonds()
  which is defined in jcontrol.js, modeled on doCatPiSB() + showCatPiSB()
  and uses:
    makeSSBondsSpt(true/false) modeled on makeCatPiSBSpt()
    makeSSBondsHelp() modeled on makeCatPiSBHelp()