Small is relative. In my experience, which may just be the way I chose to enchant things from what I've learned of Academic Magic and not solid fact, there are multiple factors to always consider. Activation method, element and its potential addition effects, duration, radius, usage. Focus on tweaking a few of those before the rest. Tweak too many things and layering the spellwork could go wrong in unexpected ways.

Wind isn't something I've worked with before so that could be interesting, but I think it might be less of a risk than lightning. Mobile shields I find always come with the problem of keeping the radius for multiple people and not accidentally harming those inside. A repelling force would be nice for projectiles.