The product line I use at the salon (Deva) does not have a hairspray. It is one of the few curl-specific lines that does not. That being said, I wouldn't be surprised if we see a spray within a year (the recent deep conditioner--Heaven in Hair--and pomade/hair dressing--Set Me Up--were added due to customer demand).
I get asked about hairspray ever so often by my clients, and I feel that if a curly client wants to use it, she or he feels that it will produce a very specific feel or look that runs contrary to a natural, soft fall of curls. What I have found through experimenting on my own hair is that one CAN utilize spray in a very effective manner while still keeping a soft feel and appearance. Again, it's a combination of two aspects: product type and method of application.
When would one use a spray?
Hairspray on curly hair is best employed when you desire your curls to have a more specific placement, e.g., curls moved away from the face so they don't fall forward, or, keeping a bit of height on top. Also, for finer hair, spray works as an added hold factor to help stave off mid-day drooping.
What type of spray do I use?
For all curly types, I recommend aerosol over pump spray. Aerosol dispenses in a much finer mist and goes on much dryer than a pump. It is easier to control the amount of spray applied with an aerosol as well as where it is applied on the head. Pump sprays are far too concentrated and prone to heaviness, which may weigh your curls down.
Also, you want to avoid sprays that are labelled "soft hold," "moisture hold," or "flexible/movable hold." These softer sprays contain a higher level of humectant, and since your cleanser, conditioner, and styler all contain softeners, a moisturizing spray is overkill and will weigh down the hair and not set properly. Look for a spray labeled "firm," "finishing," "volumizing," or "freezing." These sprays will often have the softest mist and the lowest level of moisture, so your spray will not be adding any weight to your hair.
What about silicones?
Since we are in an era where shine is everything, one is hard-pressed to find stylers without one or more type of silicone, including hairspray. Most curlies look to avoid silicones as they have a cumulative coating effect on the hair that is hard to remove and eventually leads to a dull appearance and feel. I have yet to find a hairspray that does not contain silicone. HOWEVER...the amount of silicone in a firm-hold hairspray is minimal and since you are applying only about 1/4 teaspoon total of product, only trace amounts will be applied to the hair. This is another reason to chose a firm-hold spray-- the lesser the hold factor, the higher the amount of silicone.
How do I apply hairspray?
Never apply spray wet. Wait for your hair to completely dry and for the curls to be set. My favorite method is to bend forward at the waist, shake my hair out, and spray a fine, even, quick mist all over the hair from about 6-8" away. Then, quickly scrunch your curls to avoid a "cast" feeling and to help distribute the spray. Be mindful not to over-scrunch-- stop when you feel the product is integrated. Next, flip your hair back over and tilt slightly back, shaking your curls out. Once more, mist all over about 6-8" away to set the hair away from your face. Wait a few seconds, then tilt back up to normal. If desired, you can then target specific spots, making sure to hold the product at least a few inches away to avoid over-saturation.
As with any product application, practice makes perfect. You will learn quickly what is too much and what is not enough.
As for specific brand recommendations, my personal favorite is Kenra, with either their no. 25 Volume Spray or no.26 Finishing Spray. Both products have an extremely fine mist, as well as a non-obtrusive fragrance. Kenra is a professional brand so one can purchase it from either a salon or a professional beauty supply store.
In short, if you have wanted to try a spray, but have been fearful of the look, fear not! One can indeed successfully integrate hairspray into daily styling.