Yup, Bob, should be do-able. The only issue or challenge will be the approximation of the curve using the straight frog. Lay out some flex track with the frog in the correct place underneath it and then trace the flex track.
Honestly though you may be more pleased with a handmade frog.
You don't need the aluminum jigs, just use the paper templates from fast tracks as a reference and use the flextrack sketch for your template and lots of double stick tap. Sounds like you have a points tool, so use the largest one for the frog and the fill the gap in the frog point with solder.
I only have the #6 tool and I spread the rails and fill for #4's and #5's etc.
Attached is my current project cutting and pasting a bunch of #5 and #6 turnouts and wyes to build a storage yard. to maybe give you some inspiration....