No tension problems, the smaller one goes on the end that’s always the left needle. It’s the right needle that determines the st size/gauge.
I love love LOVE magic loop, will never use a DPN or two circs again. The trick however is to have a circular needle with a long and flexible cable.
Hi Ginny
How are you?
I like both ML and two circs but each method has advantages and drawbacks. 
If you like using two circs, I found it helped using two different brands of needles - if you use different needle tips and different coloured cables, you’re much less likely to get hold of the wrong end of the wrong stick.
What I didn’t like about ML was the tendency to get slight ladders at the joins but twisting the cable lessens the strain on the stitches - link below - and I found having a quick twist really helped alot.
http://www.almostrandom.com/needlesnhooks/2005/02/06/110771136407351579/
All the Best
Ellie
http://www.countonknit.com
I’ve never seen a round or pinewheel styled blanket so I’d go with that as not only will a child have more use from a blanket then from a hat but also handmade blankets are treasures children can grow up and grow through til adults then pass on to their children. I recieved to handmade knitted or crochetted blankets and I love them, I haven’t made one only because I guess I don’t feel I have the time too…
I’m fairly new to knitting and have made many hats on 1 circular needle. I’m just about to start my first project that says I need 2 - so going to give that a go and see what I think. I didn’t realise that I could have done it on one needle anyway! I love how there can be different methods to achieve the same result - knitting rocks!
…goes off to learn how to use 2 circulars 
I don’t like the wings on magic loop, either.