Re: Aikido against strong people...
I am often that stronger person that some what to train with and some want to avoid.
Whether the waza works or not is often a matter of level.
At lower level, as long as the technique is basically correct, I tend to let it work.
At a higher level, I tend to offer more resistance.
Usually I can resist because I feel it coming.
Don't try more/harder, but less/softer.
Always connect and take balance prior to making physical contact.
Just some ideas from this side.