JohnAconSome of the extra caps seem to cover the alternative row profiles if you do for example Home, End, PgUp and PgDn for those for keys. There's also a top row Delete, so it seems all fine.
JohnAconThere's no need for a "but" since the extra keys fit the appropriate rows. It's pointless to talk about standard layouts when that part of the GMMK is not standard.