Yeah no L, just rectangular 90x40 or whatever that space works out to. A port in the bathroom would be sweet so don't right that off until you really think about it.
I've seen two protruding tanks in person before and both looked awkward, the small side view offers nothing and exposes tank seams which in reality are always ugly. Both owners of these two tanks regretted not keeping the tank flush with the wall. Plus for modern you need clean lines which will be difficult to achieve with a tank sticking out like that. Sort of gives the impression you had a tank and built the house around it rather than the other way around. Also for what it's worth a masonry feature like that isn't very modern but if it is something you want and are concerned about weight you can purchases foam or
faux panels that look identical to real stone.