I must have done something wrong in the spreadsheet..... These fins for some reason don't look much like the FB fins... could it be the sweep angle? It almost looks like a plain trapezoid, with teh rear point of the fin being at approximately (14, 4). I'll double check my numbers.
I have the rsim demo so i can't save. maybe this christams I'll get to spending some money on the real thing.... I managed to do a weird little sim last night, fins looked pretty accurate but I simmed it on a G75 and then an H128 and teh 2 flights were within 100ft of each other? Must have been my error.
Not too much selection of the 4" rounded nosecones, plus big nosecones are expensive. Scotglas has the 4" mosquito nosecone, see https://www.scotglas.com/components.htm. If you're patient and vigilant, from time-to-time you will see 4" rounded nosecones on ROL auctions.
You could also make one yourself by fiberglassing over a styrofoam mandrel. Have you done any fiberglassing yet?