One way is to use the average length and average girth to determine what the “natural” ratio is.
Since there are many avg. size studies and its usually a range but not a size, Ill simply use the random ones I found through google.
Range might be different depending on which studies you refer. For your calculations, you can adjust this.
— Source 1
L: 5.5 – 6.3 ”
G: 4.7 – 5.1 ”
There are 2 special/extreme cases:
A: 6.3 x 4.7 (max length, min girth ~ pencil look)
B: 5.5 x 5.1 (min length, max girth ~ chode look)
A: Ratio = 4.7/6.3 = 0.7460 ~75%
Meaning, if you aim for 8'' BPEL, your natural girth should be 8*0.7460 = 5.97''
B: Ratio = 5.1/5.5 = 0.9272 ~ 93%
Meaning, if you aim for 8'' BPEL, your natural girth should be 8*0.9272 = 7.42''
— Source 2
Another source states:
L: 5.16
G: 4.60
Ratio = 0.89147 ~ 89%
Meaning, with BPEL 8'', you should aim for 8*0.89147 = 7.131 ~ 7.1'' girth.
I think keeping the ratio natural at this point is counter productive. With 7” girth, you will effectively limit the pool of woman who can have enjoyable sex with you down to like 1-2%, at best.
——
These calculations are designed so that the girth measures up to BPEL - so the focus is on BPEL.
But you can switch it up, you can make girth your focus, meaning if 6” girth is what you want, you can determine the naturally appropriate length for that.
Let me do that for you:
— Source 1, case A:
Ratio = 6.3/4.7 = 1.3404 ~ 1.34
With girth 6, that would lead to 6 * 1.34 = 8.04 BPEL
— Source 1, case B:
Ratio = 5.5/5.1 = 1.0784 ~ 1.08
With girth 6, that would lead to 6 * 1.08 = 6.47 BPEL
— Source 2:
Ratio = 5.16/4.6 = 1.1217 ~ 1.12
With girth 6, that would lead to 6 * 1.12 = 6.73 BPEL
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Hope this is kind of helpful!