OK, I have worked around question 3 by arbitrarily assuming that 1C is a 1% solution. This is, of course, not precise, but it makes little difference.
By the same token, I have ignored the space that the salt takes up in the vial. Since we are talking numbers with 23 zeroes, we can afford to omit such little details.
Finally, I have assumed that the preparation of the remedy (Nat. Mur.) is made in a 10ml vial.
From this we get (because my spreadsheet uses Danish number convention, the comma ',' denotes a decimal point '.'):
Potency©Water NaCl
Potency 1 3,34E+23 2,35E+19
Potency 2 3,34E+23 2,35E+17
Potency 3 3,34E+23 2,35E+15
Potency 4 3,34E+23 2,35E+13
Potency 5 3,34E+23 2,35E+11
Potency 6 3,34E+23 2,35E+09
Potency 7 3,34E+23 2,35E+07
Potency 8 3,34E+23 2,35E+05
Potency 9 3,34E+23 2,35E+03
Potency 10 3,34E+23 2,35E+01
Potency 11 3,34E+23 2,35E-01
Potency 12 3,34E+23 2,35E-03
Potency 13 3,34E+23 2,35E-05
Potency 14 3,34E+23 2,35E-07
Potency 15 3,34E+23 2,35E-09
Potency 16 3,34E+23 2,35E-11
Potency 17 3,34E+23 2,35E-13
Potency 18 3,34E+23 2,35E-15
Potency 19 3,34E+23 2,35E-17
Potency 20 3,34E+23 2,35E-19
Potency 21 3,34E+23 2,35E-21
Potency 22 3,34E+23 2,35E-23
Potency 23 3,34E+23 2,35E-25
Potency 24 3,34E+23 2,35E-27
Potency 25 3,34E+23 2,35E-29
Potency 26 3,34E+23 2,35E-31
Potency 27 3,34E+23 2,35E-33
Potency 28 3,34E+23 2,35E-35
Potency 29 3,34E+23 2,35E-37
Potency 30 3,34E+23 2,35E-39
Note that around 11C, the number for NaCl falls below zero. At this point it can be seen as the probability that a single molecule of the mother tincture is left.
WOW! We just recalculated Avogadro's number and got it right within an order of magnitude! Not bad for a ball-park calculation

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Hans