I don't know that there is a category based on level of effectiveness of the techniques. Because my sensei told me that all the technique are very dangerous and very applicable in specific situation, where we can only learn to detect what situation for what technique by time and experience , because all the decision and the process will be happened in split second.
I also have always been told repeatedly by my sensei's that :
1. all of the technique should be done in "special way" to respect and protect our training partners who are willing to help our growth. Example : don't push on uke's elbow, aware when pulling uke's hand in shihonage, etc.
2. Everybody especially the beginners have to work hard to improve their ukemi and breakfall. Because the goal of ukemi and breakfall techniques is self protection. Especially when technique is done very fast and the projection of the throw is very hard, uke will get severely injured when they can't response well with perfect ukemi/breakfall technique. (before this, once i thought the breakfall and ukemi technique are intended for show or demonstration
But i will discuss this with my senpai's and my sensei's at the dojo, thank you for bringing up this discussion. It's really interesting. Ow btw, maybe i need to tell you that i am just a beginner in aikido , but really interested to learn many things especially from the discussions in this forum, so.. i am really sorry if i have something wrong on what i am saying here. Thanks.
If there is indeed a special way in doing this technique, I'll be very interested on your findings with your Senseis and Sempai.
I humbly suggest that you try resisting the technique WITHOUT rolling in that if you feel the forward projection, just post your leg forward instead of going into a roll. Make sure you trust your partner lest he break your arm for your 'resistance' which is not what we're looking for
. I'll post a video on this later today when I go to the dojo.