This is the way..
I replaced my thru hull strainer with an open thru hull last winter when I replaced my thru hull valve. I also added a large strainer and mounted it well above the WL. Finding space and building that mount was a challenge. The original thru hull was a flush bronze surface filled with small diameter holes. There was no strainer on the raw water side of the pump and I had added a small plastic one when I replaced the engine two years ago. It worked, stopping some grass. The new arrangement seems to work well. The strainer I now have looks large but it is easily serviced and is doing its job. I did push a small brush with AF paint up into the opening of the thru hull when I painted the bottom this spring.