I am doing Novus scroll for DRG and so far have melded just 1 grade IV determination that I had in my inventory. Now working on Liberator (UAT dropped in first week at Syrcus, just had to brag about it) that I will use while doing one of 2:

1) wait till my retainer bring back grade IV det or I get lucky at spiritbonding

or

2) add to my scroll Det, Crit, Acc using grade IV materia only at 100% chance

So far I have spent maybe 50k on my Novus scroll to get low materia I had no patience to farm but don't plan to buy any grade IV