The creative process I go through is a very organic one; One that is not limited to time constraints. In my experience the best ideas are ones that are not forced but rather ones that are "revealed". In other words I become aware of ideas rather than create them.
Your part is that you provide as much information as possible about your situation and ideas that you and/or your co-workers have already thought about.
Once I have that information, I begin my process to conceive something for you. During this process you do not pay for my services. If I do come up with something I feel will be of value to you I contact you and give any necessary sketches, drawings or even models so you can make an assessment for feasibility of the idea. From that point we negotiate as to my fees and what I produce for you.
Remember any concept or "invention" I create for you remains your intellectual property that may be patentable.