Just an FYI: I originally went with the brass/bronze screw in fittings, then switched to putting the hose on the outside with the hose clamps. I'm getting much better performance than before.
The key with reducing from 1" to 3/4" is that you want to make sure when the reduction happens that you've got the additive of the two 3/4" lines before the reduction. Thus, you have a total of 1" into 1.5" when filling, and 1.5" into 1" when draining. If you reduce 1" to 3/4", then split it, you've got 1" into 3/4" and more restriction. I hope that makes sense.