Here is what I would do If I were in your shoes.
Just get some regular aragonite dry sand, this will eventually become LS. Get mainly baserock, if you can get ahold of lace rock or tufta that is ideal. Then get as much LR as you can afford (at $200 for 20lbs that is probably all I would get). Then you add the LR to the baserock, eventually the LR will seed the baserock and the sand, then you will have a tank with all LR and all LS, this will probably take 6mo to a year.