I've had good luck using flat filters. But it seems that late season and or very dark syrup seems to over load flat s and just have to reheated and filtered again.
One thing,,,,, Ray Goodrich,, Cabot MA says to not bottle above 189 degs. As 190 degs and above that,, more sugar sand will form in bottle. That I believe I have noticed when my LP heated, water pan goes above 190 and because turning down LP doesn't right away stop raising temperature of syrup in canner.
2012 200 taps on buckets,,, Built me a 2' X 11' arch,,, hope to put most on tubing next year.
2011 100 taps on buckets, 30x 60 flat pan
2009 63 taps on buckets,,,, 30x60 flat pan