Reddit mentions of Murder Blood On The Glass Decor Bathroom Shower Curtains Halloween Home Collection Shower Curtain Waterproof Mildewproof Not Fade Polyester Fabric Red 66"X72"Inch

First, you're going to need to install a floor drain and a large hose. Like one of those fire fighting hose nozzles that are red with the rubber bumper guard. It's the only thing powerful enough to push the blood around.

Second, you'll want to install some sort of grout free tile on the walls or some acid resistant plastics. Grout sucks up DNA which can be scraped for evidence. Same with bare concrete. Acid is going to be your main cleaning agent to ensure Luminol won't reveal any issues.

Third, you'll want to hang disposable curtains to prevent splatter.

Yes, this may end up looking very sterile and medical, but you can do a few things to make it nicer. If you're in a warmer climate, you could put in a very small ceiling fan. If it's cold, you can use some decorative lights with halogen for the extra warmth. Use fancy tie backs to make the curtains look stylish.

And avoid Bosch appliances. They're terrible and the most cost effective models aren't customizable. I swear to god I'll kill the guy that made the 90 minute "wrinkle guard" setting on my dryer mandatory.

Edit: These might be fun and really throw people for a loop! https://www.amazon.com/Shower-Curtains-Collection-Waterproof-Mildewproof/dp/B01LLDPYA0