JonChesterfield parent
I'd like to know why making debian packages containing the kernel now takes substantially longer than a clean build of the kernel. That seems deeply wrong and rather reduces the joy at finding the kernel builds so quickly.
Are you building the Debian kernel with the same .config as when you build the kernel directly? If not, that's probably why. A Debian kernel build will build basically everything, mostly as modules. A kernel tailored for your specific hardware and needs will be much faster to build.
Also disabling building the _dbg package for the Debian build will significantly speed things up. Building that package takes a strangely long amount of time.