I designed my experiments using custom design platform which gave me 15 runs in total (minimum was used).
There are 4 factors:
2 level categorical
3 level categorical (two of them)
2 level numerical countinuous
The experiment itself consist of mixing matrix components step (ratio is fixed, quality of 2 of 3 matrix components is controlled by 2 factors) followed by addition of other additives (another 2 factors).
I realized that random combination of grades of matrix components results in only 6 unique matrices.
Can I mix matrices in one go and use each of them for every individual run? Or will it irrevocably spoil a whole randomness of my design?
If I will do experiments during 2 or more days, should I also use block for this split?