No, I don't think NF offers any but could be wrong. I grew up in Iowa hunting some pretty thick stuff so I know what you mean. But I preferred to let the deer come to me so I had time. I got a whole drawer full of butler creek caps. I don't care for them so I have been taking them off and tossing them in a drawer. I will see if I have some for a 56 NXS. If so make me a reasonable offer and they are yours.
I also just use the bikini covers, I would think if you have time to flip open butlers you would have time to remove the bikini cover.
Actually I think it is a little quicker at least for me.