Hello, yes cylindrical is a better translation for gilig.
I hope we didn't drifted too far from the subject, however nyekrak maybe derived from nyekreki->nyekrek->cekrek. In where I live nyekrak can be rough, thorny, etc, I don't know how it is means in other region.
I'm sorry I associated wuwung with individual rooftop which is traditionally rounded, in fact in keris terminology it should be the rooftop as a whole, hence flat
Thanks