The customer had already sourced, bought and paid for, a complete spare 30T2. Unfortunately the spare movement was botched and had the incorrect balance and cock and so wasn't usable. With unlimited funds, replacing the balance is indeed a possible solution, but with projects like this, all factors have to be considered and the best solution is typically somewhere in the middle, that being: what is the value of the watch vs how much more has to be spent on the repair, and consider as well that sourcing another balance may end up with another unusable part and more money spent.
In the future if a new complete balance is sourced, it could be installed and may only need slight trimming of the pivot lengths to fit (because it's possible that this cock is also the wrong part) or even better, a balance assembly and cock could be sourced to replace both parts.
Considering the number of botched repairs on both movements (roller table, balance staff, cock height, incorrect balance, incorrect cock, botched barrel bridge repair) I suspect that the odds of finding used parts or complete 30T2's in good condition are not great.
Thank you for the positive feedback.
Edited by a mod Jul 10, 2021