Upload & Sell: On
Russ can chime in on the practicality of this, but if the light really stinks, what about dropping the shutter way down to like 1/50th of a second and trying to get those moments when the head is still, but everything else is moving. In other words, take advantage of the bad light. Definitely a trickier type of shot to get and not for all apparatus and possibly only viable with higher end athletes, but it might work.
On the actual pictures... very nice work. Don't sweat the watermark. Photo editors at publications don't. It is not hard to look past.
Too risky. If looking to shoot creatively and get a good one every now and then, I'd say yes. But, when you are expected to get 20-30 sellable shots of every gymnast that comes through your apparatus, you MUST be conscious of shutter speed. When it comes to sales, the thinking is totally reversed compared to what we think here. Noise, lighting, cycling lights... DOES NOT MATTER. Showing a face and being in focus... DOES. Parents don't notice what we notice when it comes to the mechanics of the image. If it's in focus, has a face, and shows some sort of action in the routine... it will sell. You're not a creative shooter when it comes to youth sales. You're a dutiful shooter.
Shane... I think you did well. Some work better than others, but overall... you're on the right track with you're thinking. Lighting doesn't matter. I shot over 30,000 images in one weekend for a company last year at ISO 25,600 and the images sold like crazy. So, don't sweat it.