No.. because you are not worried about the levels of result materials like nitrite and nitrates, you are just worried about maintaining the overall colony size you've achieved, so just keep dosing as you have been, right up to the big water change. A tank can even be dosed maybe one more time -after- the big water change if you had a sudden change of plans and couldn't get the fish that day, since one day of resulting nitrates wouldn't result in much change from the effect of the big water change and of course we know the colonies would clear the ammonia and nitrite in 12 hours. As mentioned earlier, most who follow fishless cycling carefully, as you have done, find that their first stocking is quite easily handled by the biofilter that has been built.. they just see rock solid double-zeros in the days that follow the first stocking.
~~waterdrop~~
Hey Caz! No, I've never had Diamonds (that I can remember, lol, I had a basement filled with tanks as a teenager and often lost track of what I had!) They are just yet another tetra on my wish list from seeing in pictures or the occasional glimpse at a shop or swap-meet.