The Noord-Hollands Archief is an option as well, as it includes Velsen.
Earlier efforts by me during the past couple of days to post this reply including the link to this archive were unsuccessful, the reply got blocked probably due to tight security measures of the BHIC site.
However, when Googeling on: "noord-hollands archief" + dtb
you will find both the site and references tot DTB records. I do know from the Dutch site ‘openarch’ that records are indexed and scanned, in my case of the 19th century. But I don't know about all and older records.