I feel most literature on this is male oriented. The most I can find is women should not do it directly in front of males, even children but should do it on the side away from them.
How should women balance relieving outdoors and tzneuis should there be no bathroom available? I do not think I can follow the one tefach rule behind for women without risk of soiling self. I would go a bit of a distance from other people, have a lookout to watch for people coming near me to keep them away and do what I need to do and uncover as much as I need to without soiling self. I assume that is enough for tzneuis.
I try to plan to make sure I will not be in the situation to need to go behind the bushes but it happens. I once held in until I felt even my kidneys were hurting and they were hurting for a while even afterwards. I also suffered from stones in the past. I also had accidents from holding too long in the past.
I don’t know why you have this feeling that literature is male oriented. Whenever there is a difference between male and female the halacha and literature are very clear about it.
Regarding the amount that it says to uncover when relieving oneself, the commentaries say that this all depends on the person’s circumstances, the type of clothing they are wearing, and where they are. The general rule is that we should try to remain covered as much as possible, while being sure not to get ourselves soiled in any way. Of course we should try as much as possible to go somewhere, or behind something, so that we will maintain our tznius and self respect.
A person should not hold himself in, it is not healthy and disgusting therefore halacha says that we shouldn’t do this. This is known as “bal tishaktzu”
Ben Ish Chai Vayetzei 5, Kaf Hachaim O:CH 3-13. S:A O:CH 3-17.