Parachute requirements formulae

[AviosAdku]

Greetings

While designing my latest craft, I was trying to work out what parachute setup will be required but I soon discovered that there seems to be a relative lack of information on this topic that can be easily found with the majority of information being vague rules of thumb for Kerbin sea level or an admonition for a simple "guess and check" approach.
My hope is to find some more general purpose formula I can use to calculate the required parachute area for a given desired terminal velocity, vehicle mass and atmospheric density so that I can perform these calculations for other bodies or more exotic environments and manoeuvres (and perhaps find a way to work out the usefulness of a drogue chute in certain circumstances) without going through the laborious task of using cheats to test an as yet incomplete design, a prospect I am somewhat averse to, particularly in my career game.
So far, the following forum/reddit posts and subsequent discussion have provided some information as to calculations but unfortunately they don't seem to provide any hard numbers with regard to the relationship between parachute spread in symmetry grouped radial chutes and their effectiveness.

- https://forum.kerbalspaceprogram.com/index.php?/topic/156287-boring-maths-on-parachutes-in-12/
- https://www.reddit.com/r/KerbalAcademy/comments/7cfwab/parachute_calculations/

As I lack the needed understanding of the physics or the ability to figure out how to work out the game's calculations to figure out the formulae to perform the necessary calculations (Spread angle effect and parachute calculation). I thereby make this request for assistance in finding said information.

I apologise if this is in the wrong forum as I felt it could fit into either gameplay questions or general discussion

AviosAdku

--- EDIT ---

While performing some quick tests with RCS Build aid (thank you @luizsilveira for the suggestion of the mod), I can confirm that the spread angle is actually a factor for all parachutes and can affect individual parachutes as well as symmetry grouped ones. However I was unable to determine the exact effect of the spread angle which seemed to tail off with the higher symmetry levels (in testing with Mk2-R Radial Mount Parachutes, the cutoff where further angle had no effect was around 8 degrees with 6x symmetry and a 577t mass but around 6 degrees for 8x symmetry with the same mass).

Thank you so far

Edited July 19, 2020 by AviosAdku
Adding findings from RCS Build aid tests to also highlight the question of the effect of spread angle

[MrSystems]

My comment here might help:

 

[luizsilveira]

RCS Build Aid has a great parachute calculator.