Not that I am working for a university, I have access to a good library. I have been reading up on diesel engine design and technology. The books don't really talk much about multifuel capability (besides the need for higher compression). They do compare combustion pressure versus crank angle for various compression ratios. The higher the compression ratio, the higher the combustion pressure peak and the quicker it occurs. I think that you would do well to decrease the compression ratio to a more typical 17:1. The books' rule of thumb is to set the compression ratio at the minimum required for starting. I'd bet that the timing on the multi is also different than the tractor because of the compression ratio.
There is an SAE paper on the development of the LDS engine which I have requested via inter-library loan. I'll report on the details when I receive it.