Why just DC1? Is the issue that you couldn't be sure whether DC2 would get a place?
My children both go to grammar schools, but we don't live in a grammar school area as such. These grammar schools would be considered "super selective" and the nearby secondary schools are genuine - and excellent - comprehensives. I would have been very happy to send my children there and very nearly did, despite the grammar school offers. I would not have been at all worried about one getting and and one not.
Despite my children being at grammar schools, I confess that I think a grammar school based education system is basically wrong and bad for society as a whole. It may benefit a minority, but even that isn't clear - grammar school children in all likelihood would do just as well, or almost as well, at a decent comprehensive.
Does this make me a raging hypocrite? Possibly, and I am a bit uncomfortable and conflicted about it. However, I don't think that the existence of a few super-selective schools has anything like the negative impact of a complete grammar school system which takes the entire top 20% or so and inevitably labels the rest as failures. That doesn't happen here. There are children getting straight As, even straight A* at the local comprehensive. Second, I think most of us at times take advantage of systems that we don't think are ideal eg. I think that people with high salaries (including myself) should pay higher taxes, but I don't tick the box on the tax return which allows you to do so voluntarily.
Similarly, despite being basically anti-grammar schools, from a personal perspective I thought my daughter would be socially more comfortable at the grammar and my son would benefit from the competition. I also liked the idea of more racial and cultural diversity at the grammar. So I sent them, despite not being 100% at ease with the decision.