Just asking as you know more about this than any of us dickheads, but do FSG entertain signing on bonuses?
In summary, not opposed IN PRINCIPLE to a one-off, up-front payment, but it's difficult to structure that and the club won't generally do a standard-form signing-on fee.
The thing about a signing-on fee is that it has to be paid in every year of the contract and remains due even if the player leaves the club. So if the player want's a £2m signing on fee, then you have to payment them £2m a year for five years (or whatever the contract length is), even if they turn out to be shite and you bin them off after one year.
So we've always preferred to try to structure a bonus that can easily be earned at the end of the first year (and typically will remain due even if the player leaves after 12 months, so it's basically guaranteed from his perspective).
There's a crazy tension with the FA in that they insist that signing on fees are paid in each year of the contract, and they won't entertain a one-off, up-front payment at the start of a contract. So in the case of the easily earned, year-one bonus, you still can't pay it until after the end of the season. They don't like players getting a big lump sum up-front, but they don't mind if it's paid every year. Which makes zero sense, but also tends to deter clubs from agreeing them.
There was one deal we did where the player didn't join us immediately and we arranged for his existing club to pay him a one-off bonus which we funded by an extra transfer fee (the bonus essentially enhanced his wages in that season to what they would have been if he'd joined us immediately). In that case the other club was overseas so they had more flexibility.
I think we did agree to signing-on fees on a couple of Bosman's - the signing-on fee substituted for the transfer fee and also enabled us to keep the core, weekly wage more in line with the rest of the squad. Madrid have apparently done this to the extreme with Mbappe.
That's for players. For staff / coaches, where there's total flexibility, I don't believe they'd have an issue doing it.