I have tried all sorts of different options of hats, scarves, mittens, gloves, etc including 3 different types of balaclava's. For 40-50 the problem you will find is trying to not overdress. You will heat up and need to shed clothing. A good rule of thumb is you should feel a bit cool when you start. As soon as you start pedaling and get the blood flowing your going to heat up quick.

Here is what I have settled on that works best for me.
I wear a freeze out helmet liner. Yes, for motorcyle-yes dirt cheap.
FREEZE-OUT - Helmet Liner - Head/Neck - Base Layers - Street - Cycle Gear


For my face I use a shemagh (ebay,amazon,pakistan,etc). This works much better than a balaclava since you can loosen it, wrap it multiple times, or shed it completely as you warm up/cool down. The problem with a balaclava is if you get too hot it's hard to get it off your face and keep your head warm.

For my hands I use
FREEZE-OUT - Women's Inner Glove Liners - Gloves - Base Layers - Street - Cycle Gear

I use the men's version but same glove. These work great for keeping the cool air off my hands. If it drops below 40 I will switch to my cool weather rain gloves.

http://www.amazon.com/Glacier-Glove-Kenai-Basic-Extra/dp/B00GN1WKF8/ref=sr_1_4?s=sporting-goods&ie=UTF8&qid=1453409024&sr=1-4&keywords=Glacier+Glove+Kenai+Basic+Neoprene+Fishing+Glove
After years of cycling and motorcycling I now go for wet is ok if I stay warm over the never ending battle of waterproof gear. They work great for cold weather too.

For my feet I use my normal shoes and go with something like this.
Amazon.com: NRS HydroSkin Wetsocks: Sports & Outdoors
I use it for the insulation value to keep my feet warm.

For my body at 50 I wear a fleece shirt topped with a thin nylon jacket and pants. if it is 40-49 I will add a fleece pants under the nylon pants.