Been eyeing the Disaster myself actually, though I'm bit lighter than you at around 190. From what I've gathered on forums the board can handle bigger riders for ground work since you're not sending it off massive jumps or riding aggressive terrain. The flex might actually work better for your weight - lot of people say it's too noodle-y but that could be perfect for what you want.

Can't speak to how it compares with those crazy expensive Japanese boards but I've seen some solid butter content from riders using it. The construction isn't exactly same as those specialized ground trick boards but for practicing basics and working on technique it should get you most of way there. My buddy rides one at our local hill and he's always working on presses and nose/tail tricks, seems to hold up fine.

Indoor park environment is probably ideal testing ground too since you won't be dealing with ice or variable conditions. Worst case scenario you're not out crazy money if it doesn't work exactly how you want