Hiya OSB.
We always (should) know your a/c type and have a fair idea of the likely a/c performance. Speaking from a TMA environment up to around FL100 I'd anticipate 1-2000 ft/min from a 146, and if asked to expedite around 2.5-3000 ft/min.
We're aware that you're not going to accelerate past Mach 1, (or even 0.1..) and it's not usually a problem. What that does give you 146 sorts though is a good ROC/mile which gives us other options to offer early climb.