If you are willing to sacrifice a 6point socket or a wrench, just take a grinder to thin it out.

Salim

 

Salim,
Just got home, I think the Lowes Kobalt 15/16-in 12-point combo wrench will work. Item #337622Model #85616 Just got to find a good wedge to keep the wrench in place (I think I have a wood stake in the backyard) so it does not come off while torque-ing it.
HD was closest so I bought the husky, too fat! Went back out to Autozone, the Duralast was thinner walled but still looked too thick - got it anyway, then to NAPA since I had to pick up the replacement drain plug anyway, their house brand was thicker than the Duralast . Last stop was Lowes and picked up the Kobalt. Will try it after I eat lunch and will post the results. Item #337622Model #85616

 

Ok the Lowes Kobalt 15/16-in 12-point combo wrench works! Item #337622Model #85616
I placed the wrench then hammered in a wood stake (the side triangular side that goes into the ground) or you can use any wedge shaped material that's not too hard, the key is that it needs to get wedged right on top of the drain plug bolt head (also box wrench) and between the chassis/body member. This way it keeps the box wrench on the drain plug and prevents it from slipping off!

My only concern now is that the NAPA replacement magnetic bolt in post #10 above is too long. Have many used this? I guess I will use the plastic washer that it came with plus the crush washer. Hope this does not leak when used this way or is too long and something inside hits it.

 

How did this work out? Did you have a leak after using both washers?

 

How did this work out? Any leaking?

 

Sorry i missed your post, it's been fine, no leaks!