64 Valiant 2 Door Sedan Carpet Questions

Got my new carpet laid out in the Valiant tonight to sit there a few days to settle down and lay down against the floor before I start trimming and making holes. The only "landmark" I can see on the carpet is the "scallop" for the dimmer switch in the jute padding on the back side. That's great, as I can use that to locate the entire front piece. No problem. I got this carpet cut long, so that I could cut it how I want to and not have any short sides. So, here's my question. It's been a "while" since I took the sill plates off and removed the factory rubber mat. Does the carpet go under the inner sill plates? I certainly assume so. This car has inner and outer plates. What holds the carpet in place up on the toe boards? If I have to use an adhesive, I don't want something that has a gorilla hold, as if I ever have to remove the carpet, I don't want a fight. Also, what's a GOOD carpet cutting tool? I don't mean a POS utility knife. My hands are gettin old and arthritic and they HURT, so I need something that cuts it GOOD. Thanks for any insight.