Re: The Problem with Being a Big Guy
Hi Scott, just chiming in. I don't consider myself a big guy, but at 5'9" and 215, I'm pretty solid, with low center of gravity and along with the frame I have some grappler tendencies from my childhood through my early 20s. Two things I like about your line of inquiry is the way you're asking the question to get insight and then responding to each person. There's plenty of folks that already "know" the answer to the question they're asking and are really just looking for agreement. In addition, I get the feeling you are on a continuous process of "working it out" and I think that's a fantastic attitude to hold onto, no matter what avocation or art you're into.
Anyways, soapboxiness aside - my response would be to keep along with genuinely trying to "connect" to the other person, as it sounds like you're trying to do. An additional component is to train yourself to be responsive, not because you're forced to go somewhere, not because you're helpless (though you may feel like it), but that ukemi is your way of receiving the technique to facilitate their training and keep yourself safe, composed and ready/able to counter/respond instantly.
This is a tricky balance because it is absolutely tailored to who you're working with. Someone that's just figuring it out, you can help them by giving up your center more - forcing them to feel it through the connection you're imposing on them (think of it, uke is the receiver, one who "fits in", but they typically establish the connection through which nage "enters"), while still being composed and able to respond . . there's a lot of room for study, there. Someone that's more aggressive, you still enable their training, but you keep yourself safe and if they have a clue, they'll understand that you aren't a helpless dummy that they can have their way with.
But I think it comes from giving a clean "attack" by which you create the connection (starting from a dumb force that someone can work with - hence the somewhat rudimentary nature of basic aikido attacks), nage trains to enter it appropriately (ideally off-balancing you before contact is even made), you enable the training by continuing to "fit in appropriately" with the connection and nage finishes the engagement.
There's a lot of room for interesting study in this space . . but it's admittedly leaving aside some of the less "structured" components involving randori, testing in a more free form environment, working things out against other martial arts/practitioners (all additionally important areas of training in the combative developmental sense, but YMMV) . . and to be honest, within the aikido space and partner practice, I think the above considerations are among the most important, especially as related to how you're training your body to relax, generate soft power, etc.
Anyways, thanks for getting me thinking and spewing forth - good luck in your journey!