OK, a few assumptions that you have made are not correct:
- It is true that Logic will only use 8 cores, real or virtual. Therefore on the latest dual socket machines you would only be able to use a third of the power available to you. However, if you use VE Pro you could use all this power, as VE Pro can use as many cores as you have.
- Even if you run Logic 32bit you can still run VE pro as 64bit, thereby using all the RAM you have. If you really want to do high end orchestral stuff you would run out of RAM pretty quickly with 12GB, never mind 6GB.
- I assume that talking about 3GB RAM sticks was a typo.
- The pre-load of the sample that is loaded into RAM is fixed. You have no control over that.
DG