Don't recommend going over 15"-16" tall, keep it below your knees. I've been bow fishing over 30 years and have put platforms on 3 different boats and found that if they are any taller, you'll hit your bow on them on close shots.
I also wrap mine with pipe insulation and dark colored duct tape so they're padded and won't damage your bow or you if you do hit them.
And if you can, make the platform just high enough to get your lights UNDER the platform.
If you put the lights underneath the platform, when the weather gets warm and the bugs are in full force, the bugs stay down below your knees.
If the lights are attached to your railing, the bugs will be in your face all night long.
I have also had two people go overboard, during the day, in broad daylight, (never even came close to have it happen at night), even with the railings but the padding helped keep them from getting hurt.
One guy was my brother in law. He learned the hard way when he didn't listen to what I told him to do. I told him to put his forward leg (shin) against the railing and firmly plant his foot so he'd be 'anchored' in case we hit something. But instead he was standing back away from the railing and we hit a stump doing about one (1) MPH. He skipped forward and the railing actually tripped him. If he'd had his leg against the railing and his front foot firmly planted it probably wouldn't have happened. He went under the boat and had to push away from it to get back to the surface. WE laughed until we cried after we got him back in the boat and realized he was okay. His son was standing next to him and couldn't stop him from going overboard because it happened so fast. But his son had his leg and foot planted and stayed dry.
The second guy that went out was the only person with me that day. He was actually sitting down in a padded boat seat mounted on a tall pedestal post on the platform. I custom made the pedestal from two pieces of steel pipe and it's 20" long/tall and when you put a padded seat on it your feet barely touch the platform. I made it that way thinking of my brother in law (the one who went swimming) who has a bad back and doesn't bend over very well. So that way he could shoot sitting down without hitting his bow on the railing.
Little did I know it would end up catapultimg someone into the water. I fell forward when we hit the stump and when I looked up to yell at the guy for not watching for stumps, he was gone and the seat was no longer on the pedestal mount. It was flipped upside down, laying on the platform. We also hit a stump that time at about one (1) MPH and he slid off the seat, his legs hit the railing, folding his feet underneath his butt and he went head first into ice cold water. He said he didn't have a chance to grab anything and out he went.
In both cases, it was early April and about 45 degrees out and the water was high and muddy and the water temp was about 40 degrees. Thank God the water was only about four feet deep. The guys were both okay. Cold and wet, but okay. I can still see their faces as I pulled them into the boat.
One guy lost his sunglasses but my brother in law looked like he never went overboard. He was still wearing his hat and had his sunglasses on his face. BOTH of their faces were plastered with black mud. The two have never met but said the two exact same things when I got them back into the boat; "What the hell did we hit?" and "SON of a BITCH that water's cold". All I could do is laugh at them both for asking me, the guy standing in the back of the boat, what we hit. Serves em right for not paying attention. And in both cases we had to fish around with the muck poles to find their bows in the black muck.