Something

report.combo.mem.name=Available Memory MS and SINF
report.combo.mem.columns=sinfMemAvailMB, memorySize
report.combo.mem.type=node
report.combo.mem.command=--title="Available Memory MS and SINF" \
 DEF:memorySize={rrd1}:memorySize:AVERAGE \
 CDEF:sizeMB=memorySize,1024,/ \
 DEF:availmem={rrd2}:sinfMemAvailMB:AVERAGE \
 LINE2:availmem#ff0000:"SINF Memory (MB)" \
 GPRINT:availmem:AVERAGE:"Avg \\: %10.2lf %s" \
 GPRINT:availmem:MIN:"Min \\: %10.2lf %s" \
 GPRINT:availmem:MAX:"Max \\: %10.2lf %s\\n"
 LINE2:sizeMB#0000ff:"MS Memory (MB)" \
 GPRINT:sizeMB:AVERAGE:" Avg  \\: %8.2lf %s" \
 GPRINT:sizeMB:MIN:"Min  \\: %8.2lf %s" \
 GPRINT:sizeMB:MAX:"Max  \\: %8.2lf %s\\n"