Yes, I agree it is very much possible to beat H.N. Elly's stage with Sayaka alone. The stage (not the boss fight) becomes difficult for her only because if you time your jump incorrectly you will either collide with a flying enemy or a TV will fall on you as soon as you jump over a pit. Her special dash is dangerous to use too much here because it turns your life bar blue with every use.
That said, I've never experienced getting Sayaka permanently killed, even against H.N. Elly while I was still playing in the past. This also means I've never tried the secret Oktavia stage, however.
As for your problem with Madoka in Elsa Maria's stage, it's really not that hard if you use her fully charged piercing strong attack a lot, and use it in mid-air, aiming for the heads of the shadow enemies. The heads are mostly lined up so your piercing shots will quickly take out a bunch of them. Run and jump around a bit to evade attacks, find shooting opportunities and good charging spots.
I've never beaten the game using Mami, as I find her much harder to use than Madoka. Haven't done it with Homura either, it's true that she has too little soul limit reserves. I think she's great for multiplayer, though.
Co-op with you online sounds like a good idea, though it has been a few months since I last played Grief Syndrome. Are you using Hamachi + GSOnline as well? I come from an archipelago country in the northeast part of Southeast Asia. I assume you're from one of the countries just to the south of mine.
just read you Grief Syndrome discussion with Trpiple_R
for me it Sayaka>Kyoko>Madoka>Mami>Homura
with Sayaka and Kyoko, i'm beat the whole game like it nothing, even in Kristen stage using Sayaka. her dash skill can avoid most pitfall.
with Madoka, i'm have huge problem with Elsa Maria stage, it really hard to use normal attack to hit enemy's head, i'm usually got through that stage with madoka have about just 1000->5000 soul imit left
Mami is a bit harder to beat the whole game, but at least she fine on every stage
Homura have so little soul limit that i have to try many time to beat the game with her, the hardest stage to beat with Homura was Kristen.
oh and do you want to play co-op? i'm from Southeast Asia too, which country are you from?
yeah, she is just too cute. the moment i see this pic as a avatar of someone i immediately use tineye to findout who she is . if you want full-size pic of my avatar, it here. now i'm requesting this pic as my sig
Say, your avatar is Tsukiko from the light novel & manga Hentai Ouji to Warawanai Neko, isn't it?
I've been enjoying the manga version for a while. She's really cute, though I don't see her around a lot as an avatar. Great choice, I must add.