Well ... you really do not need stock kernel config when building your own. Generic kernels are built to work on practically every possible hardware configuration that support Linux. While your custom kernel is just the opposite - it is supposed to be lean and contain only drivers and features you need.
First. Be prepared to spend time, hours. Kernel is the most important part of your GNU/Linux installation.
Second. There is a great site to help you, http://kmuto.jp/debian/hcl/
Third. Learn about make targets after installing sources. For instance, make allnoconfig
will give you the leanest config to start with.
Fourth. In most cases you can boot your custom kernel without initramfs.