After reading this post, I figure I would use the same approach. A simple 3rd order filter, but with slightly different design parameters. I used 98MHz center frequency and wanted the edges to be -6dB. This will probably not be enough, but I didn't want to put so much filtering on it that I lose the nearby air-traffic band just above that.
I plan on receiving several of these filters, so it will be relatively easy to adjust them. I may consider assembling a test rig so I don't have to solder these into a connector to test them out. Or perhaps I will just make a larger sized board that I can solder individual SMA connectors on either end.
I put together a simple schematic with some extra components just in case:
And then copied over most of the layout of the TinyLNA like board outline, copper pours, solder mask around the outside, etc.
This came together pretty quickly since I had all of the design files from the TinyLNA. Considering the cost will be the same (80 cents for 3 boards), I figure I can go ahead and order some. Even if they are a disaster, it's trivial to fix.