I think it's only a good idea in theory.
My motivations when I wanted a partner, were purely to be observed to do it correctly because I manage to fuck up things that are second nature to most people, for no discernible or mentally diagnosed reason. So I would often talk to people for a bit, realise they were too young or struck me as not being someone who would carry out my dream (selfish) of us both doing our methods at the same time, repeating the measurements back at one another and confirming we'd got it all right and there being no horseplay or 'one last sightseeing trip'.
Honestly, if there existed a suicide service in which I could just hire someone to say 'Jigsaw, you've reached for the table salt instead of the SN' I would.
But reality is, if I found someone in their twenties like me, one of us would be panicking and saying 'hey let's give it another day/go for a walk in the park' etc and I'm really not ruling out myself as the person saying this... the chances of the two of you being absolutely ready on a decided upon date are slim to none. Think of all the times something great has happened to you and it's pulled you out- even slightly- of your desire to die. For all you know, the person you've met up with to die has received a promotion the day before, or somehow has renewed hope. You could find yourself preparing your method whilst they try to convince themselves they don't feel good about life most of the time.
On the other hand, I 'met' two cis men I considered partnering with, and both of them wanted to 'get to know me first' which I found strange and a thousand leagues away from what I wanted, which was to say hi, talk about how great it would be to get drunk first, lament the fact we couldn't and then just do it.
I think suicide is such a deeply personal choice, and I ultimately wouldn't want the muddle of someone else being involved. I found myself crying when I talked on the phone to one of them and they told me their reasons. It was too much.
Also, It sounds vain, but I prefer the tragedy of my doing it by myself, over the confusion that would be '25 year old woman, found with 33 year old man'
Really wouldn't want my parents scratching their head over why John Smith and I had paired up to die, having this forum be implicated more than it already (likely) would be and the limelight stolen from my wonderfully Victorian-mourning style death scene.
Also would be terrified in the last moments someone would grab my hand and I wouldn't have the energy to shrug them off. So I thought privately to myself 'well when I've taken it I'll immediately go to the bathroom and lock the door so they can't touch me', but then I thought of what I'd be depriving this hypothetical person...
I've been lucky enough to be able to confidently say if I chose to die with someone, there'd be no need for emotion to play a role. Granted, I lost that love, and now anything that masquerades as it makes me feel a bit sick... but others haven't. The emotional needs of both me and this other person are unlikely to be met in a partnering situation, and it'd break my heart if someone wanted to rest their head on my shoulder because they were scared and I clammed up.
I don't know. Sometimes I toy with the idea of posting something in the Partners thread looking for a woman/non-binary person...but ultimately I think the partners dream is dead for me.