Buy a quality plasic/plywood blade for your table saw. The cleanliness of cut really helps the finishing process.
Found these:
http://auveco.com/eSource/ecom/common/prodesc/pdf/4.pdf (part# 12213)
at my local True Value for $8USD for a box of 100, my fascia is black so these are a perfect match.
Clamped the acrylic firmly in place an drilled a clearance hole with the absolute minimum clearance. My concern was that excess slop would cause cracking because the washer tension would be uneven on the plastic. I was careful to leave 0.75 inch from the edge and spaced screws about eight inches apart although I might go more like twelve or sixteen inches between if there was no curve introducing tension. My concern was to spread the tension evenly around the curve so as not to unduly stress any one point along the way.
My fascia is only 2.5 inches high (half inch plywood on a 1x2 plus half inch foam) covered with hardboard. Plastic stands seven inches tall above the nominal scenery, just enough to keep coonhound nose and tail from damaging things. On curved sections I did not create 'flame edges' because I thought it could make it brittle. Straight section did get flame edges because it was cut from inside of the sheet, and I wanted the top to be clean like the factory edges the curved ones have. The bottom edge is left raw, just as cut because it is covered by the fabric valance...