Have cutworms gotten to my sunflowers?

[william babinski]

I'm rather new to gardening, and am trying my hand at growing some American Giant sunflowers. I've noticed a LOT of holes appearing in my leaves. Some are not completely eaten through which I've been told is also a sign of leaf miners. I have also noticed some of my plants are leaning pretty severely which I would think is a sign they've been cut down by cutworms. If this is the case is there a way to salvage them, or at the very least check them to be sure without disturbing them too much? I have some BT which I plan to apply this afternoon, which I've heard treats both cutworms and leaf miners, is this true? Also my sprouts seem rather tall and I would like to move onto thinning, but would I set myself back too far if I waited another week or so? I'd like to treat as many plants with the BT to increase the amount ingested by the pest, and I plan to leave the leaves treated for about two days, is this wise? I know that you ideally dont want to water after applying, but I'm somewhat concerned because I'm growing them outside in Dallas, and I dont want the heat to damage them too much. Sorry for all the questions (as well as if some are a bit stupid), but I would really appreciate any help or information!