We may have not mentioned why sust. isn't so good - the half life of it is essentially that of test. prop. So, you have to inject it EOD to really realize it's potential.
Regarding 2 methyls - yeah, it's because of heptatoxicity. M1T is some bad ****, but SD isn't so nice itself.
You'd be doing some real damage to your liver if taking both of these oral steroids.
M1T is just bad all around, I'd never take it.