This is a very important question because it is based on the current limitations of hardware. Obviously the more computers available the better. This is probably no help since you are trying to create an ideal template, but I gave that up and instead am trying to be practical in a dirty way. I have been rewriting templates for each individual piece, rather than creating a general orchestral template. Also, I use the mod wheel string patches a lot since they are very expressive, and relatively low in RAM useage. I stopped trying to be "strict" in writing legato, because it actually doesn't sound as good as being very loose and doing a lot of "fake" overlap legato combined with a few instances of the real thing. And you find you don't need all the legato instruments depending on the piece in question. For example - basses. Honestly, do you always need legato basses? I rarely do unless it is a soli. Also, I always use mono solo instruments which I know are frowned upon by some people, yet I think sound correct in relation to ensemble imaging and are of course half the size.
Anyway, it is interesting to hear various approaches to this very basic problem - a very useful thread!
Anyway, it is interesting to hear various approaches to this very basic problem - a very useful thread!