Cutting acrylic for portlights

[iansan5653]

It's about time to replace the surface mounted acrylic portlights on my Freedom 21. They're crazed, cracked, leaking, and the screws keep falling out. I plan to forgo mechanical fasteners in favor of Dow Corning 795 sealant as described here.

I'm pretty sure I can handle this, but the only thing I'm stuck on is how to cut and prep the new pieces. They aren't simple shapes (see the attached image) and they are pretty long, so I think I have to just remove them and use the existing portlights as templates (as opposed to measuring them and sending dimensions to a fabricator).

If I pay someone to do this, I'll have to deliver them one of the current pieces for them to trace. That would take a couple days and there's always the risk of rain so I'd have to tarp over the opening. Then I have to deal with duct tape residue, the potential for theft, etc. Not really a good option.

So I think my only choice is to try cutting them out myself and get it all done in one weekend. I assume I can do it with a jigsaw (though I'll have to buy one) but I've never cut acrylic before and I'm nervous about ruining a large, expensive sheet of acrylic.

I don't really have a specific question here, but any general tips on purchasing, cutting, and finishing large acrylic pieces would be greatly appreciated!