I own a Tachihara 4x5 and I wouldn't want to add any weight besides a lightweight lens to the front standard. My 8x10 lenses stress it.

I have read that some Shen Haos and Chaminox's may be made to take a Sinar shutter. I would look at a Chaminox.

As far as what Dan Fromm is telling you, I know Dan from Large Format Photography Forum and he is one of the local experts so I would definitely trust his opinion.