With respect to a percent number, that is probably spot on for 2D sections and for parts where the chord doesn't change much.
When it comes to other applications it may be as likely a set number. In other words your wing TE may be somewhere between a tenth and a quarter of an inch and possibly...
The tile system used to require a lot of touch labor during refurb. I've heard there have been some major improvements between the system as initially implemented and the current installation.
That was a major focus with some of the now defuncted follow on / replacement programs: to get a...
The reality is that aerodynamicist always (99.99% of the time) use the NACA tabular form or otherwise give out a pointy TE airfoil and the design and/or manufacturing group always open up the trailing edge to something reasonable to avoid knife edged parts.
It helps keep the assembly mechanics...