Wow. Can't see it, huh?
I'm sitting here busily fitting a Chinese red dot scope on to a hundred plus year old Austrian-Hungarian empire calvary trooper's .331 caliber saddle-carbine and you want me to stop what I'm doing and go take you a picture of an in-line fuel filter hose routing?
Of course you can't stick a fuel filter in the little short existing line that you've got -- think about it a bit, the filter is almost as long as your existing fuel line.
Improvise a bit, be creative.
All I did was take about 8 inches of standard old stiff automotive fuel hose, come out the side of the carburetor, go up under the seat, come about in a loop and come back to the outlet side of the large clear fuel filter. Loop is big so the hose never gets crimped, ever. A short piece of hose goes from the petc0ck to the inlet side of the fuel filter.
It's a piece of cake compared to putting optics on a straight pull goose-stepper saddle carbine, believe me.
Oldfeller