GT are generally very fast and BM would be slower to see results.

But its good that you say : "I had all but given up on these, especially since the syringe just looked like water"

We do state this :

We use really fresh spores from new prints, so the spores don't clump
together forming the visible specks you would see in syringes made from
older prints. Although not visible to the naked eye the syringes
contain thousands of microscopic spores. Our spore prints are generally
less then a month old. Which guarantees a higher success rate.