From what I understand you've managed to get rid of the lines you don't need, not sure what method you used but you could use this option in props.conf to get rid of the lines at the start:
PREAMBLE_REGEX = <regex>
* A regular expression that lets Splunk software ignore "preamble lines",
or lines that occur before lines that represent structured data.
* When set, Splunk software ignores these preamble lines,
based on the pattern you specify.
* Default: not set
If you want to tell Splunk to read the header from a specific line you can use the following options in props.conf :
HEADER_FIELD_LINE_NUMBER = <integer>
* The line number of the line within the specified file or source that
contains the header fields.
* If set to 0, Splunk software attempts to
locate the header fields within the file automatically.
* Default: 0
You can set it to 6 if it's the 6th line that you need.