How to create custom composition guides

[VulpineVisions]

Hi!
I would like to create a composition guide for Gimp, but I couldn't find anywhere stating how.

For clarifications, I would like to create the composition guides used with the crop tool, i.e. my custom version of the Rule of thirds, Golden sections etc. but with my own proportions.  I've attached two images highlighting what I am mean, I would like to create a custom of those.

I am aware of that one can use vertical and horizontal guides by going to the Image Menu > Guides > New Guides, but that is not the kind I want to use. Neither would I like to use configurable Grid by View > Show Grid. 

Thank you in advance

[rich2005]

(9 hours ago)VulpineVisions Wrote: Hi!
I would like to create a composition guide for Gimp, but I couldn't find anywhere stating how.

For clarifications, I would like to create the composition guides used with the crop tool, i.e. my custom version of the Rule of thirds, Golden sections etc. but with my own proportions.
....snip....

As far as I know, that is not possible.  I think the crop tool guides are hard-coded into gimp.