There is a Hand Held Calculator on the website link below that is very user friendly and can layout just about anything, including Large Radius Layout, see page from manual attached. You just input the dimensions it prompts you for, and it will give you all the layout dimension's you need for the layout. You don't need to know the math and its Dead Accurate. You can use the Layout Manual that comes with it like a computer monitor for visual instruction and direction. It will also layout Square to Rounds, Round Elbows, Intersecting TEE's at any angle including the HOLE layout, Stair Cases, handrails and much more. It always reads dimensions in DECIMAL form 1st, then in FRACTIONAL form 2nd, to the closest 1/32",+/- 1/64". This is for the person that doesn't know his/her Decimal readouts. It also has Utility programs for Drill & Tap sizes, Metric Conversions, Pulley sizes, including RPM and Belt lengths and more. This is a hell of a tool for people that don't have any layout experience or know the math. The site shows all the pages in the manual. Be sure to read all the "NOTES" in the pages, it helps things make sense. This Calculator is a Real Tool, its not a gimmick or a toy. Its worth a look at.
http://www.sheetmetallayoutcalculator.com