What’s the Best Way to Join Wide Slabs for My Workbench?

I'm constructing an 8-foot long and 22-inch wide workbench using 5 ¹⁸" thick solid slabs from two trunk segments that aren't the full length. My main concern is how to effectively join the end grain of these slabs since they're wider than they are tall (specifically, about four times wider). I need this joint to hold up well for years, especially considering the wear from chiseling and hammering. I'm aiming for a non-laminated version of Chris Schwarz's 'Anarchist's Workbench,' which is a Roubo type bench. Each half of the bench will only be supported by two draw-bore tenoned legs. Given the dimensions and design, should I stick with the kanawa tsugi joint I've been studying, or is there a better alternative to ensure durability?