I use to run a inline 6 and I used one like shown above, no 2nd filter.
If money is not a option, then a Racor is the bet and they come 10 micron and have the clear bowl on the bottom o drain the water from. Thats what I have now.
A few of us got them from a guy on ebay for a good price, but I think they are a bit small for your inline? Really I think its a tad small for my O/B also?? We will see.
The link to the guy on ebay is
http://cgi.ebay.com/ebaymotors/Racor...spagenameZWD1V