I have a 272 sailfish. Very similar but I do know your livewell is a little different. Access to all the hoses aren’t really that bad on mine. I have an inspection port where I believe you have your battery switches, behind there access to the bottom hose. Then for the two side hoses on the tank I have access to those by taking out the little panel that the wash down valve is attached too. Once the hoses are off the livewell you can unscrew it and remove the entire thing. With that out, for me anyway, I can reach and/or climb in the hole to change all the hoses. I believe grady used 3/4” wet exhaust hose on both the livewell feed and wash down. The drain i want to say is 1.5”
On another note, how did the marina replace the scupper hoses on the starboard side? I’m assuming they cut an inspection plate somewhere?