Because of the personalized nature, you can end up with elements that make it impossible.

For example, "VII" and "V" is forced by Roman Numerals needing to multiply to 35. Then, my chess puzzle was "Rf7+"

The atomic numbers - V: 23, I: 53, Rf: 104

2×23+2×53+104 adds to a number over 200, which is frustrating because it seems like there should be a trick, or it should at least be solvable

you can just use switch to XXXV. No I needed.

Work out what you must have based on the rules, list them out, then subtract from 200.

For me, V and VII from the roman numerals = 152 so I needed 48. Did He and Pd. Then of course a later rule came along.