This is a tricky subject because gender is a tricky subject. Lets lay out a bit of groundwork first.
There are (from what I have seen and researched) five different genders. Male, Female, TransMale, TransFemale, and Genderqueer. These exist independently of masculinity, femininity, and sexuality. A biological male can feel male, be feminine, and be attracted to women. Likewise, a biological male can feel female, be masculine, and be attracted to women. I would also like to point out that I "separated" TransMale and TransFemale into their own category to reduce confusion, they both belong to the over-category of Male and Female respectively, but have their own experiences and nuances which I will never be aware of due to my sex and gender matching up. Genderqueer is a confusing mess of things that I don't entirely understand, but which I will try to provide an answer for (as best I can)
I will start out by saying that Traditionalists are going to be a bit more rigid on this topic. I can't speak for them, but from what I have gathered your biological sex will be your role in the rite and will determine what rites you can participate in.
As a Revivalist (which puts me in the "Reformed" category I suppose) I realize that gender roles need to be adapted and changed accordingly yet they do not need to be abolished or done away with.
Men and TransMen should participate in the rites (if they so choose) that were for and participated were participated exclusively in by men. They should not attempt to participate in the rites of women nor should they attempt to peek in or spy on what exactly happens during these rites.
Women and TransWomen should participate in the rites (if they so choose) that were for and that were participated exclusively in by women. Likewise, they should not attempt to participate in the rites of men, nor should they attempt peek in or spy on what exactly happens during these rites.
During rituals that call for men and women to behave in a particular way, you should go with what gender you are living as. If you are a (biological) man who hasn't yet transitioned or begun to transition, do the male roles. Likewise for women. This is an instance where group cohesion takes precedent over individual comfort. I'd also suggest speaking with the priest or priestess who will be leading the ritual about it, they may have some insight or suggestions for you. The last thing most people want is for a member of their Demos to feel excluded or othered. Just look at it as wearing clothes that much your current gender, one day it will change, but until then it is best to stick with your "role" in the ritual/rite for the sake of the entire group.
That is one of the things about being part of a group, occasionally you may have to do something that isn't ideal for you for the purpose of group unity and cohesion. Also realize that it won't be forever.
As for people who are genderqueer, consult the Hier (Priest) leading the ritual and ask them where they would like you. They will make a judgement call on that.
I hope whoever read this enjoyed it. As always, I'm eager to have comments on this, and discussion. It is still an issue I'm trying to sort out, and if I go the direction I want, will likely have to face head-on.