Krelldog, take heart my friend. By way of encouragement :
I use a T/T of almost identical mass/config.
It is situated in the worst possible place – a corner.
There is an ML active bass cabinet right next to the T/T (Vantage)
The stand simply consists of 3x tri-spiked levels, 50mm thick solid oak throughout, set on a solid concrete floor.
Even at peak SPLs of 95db (measured) at 6 metres there is no trace of feedback. (Not that I routinely listen at such volumes, I prefer to retain my hearing! ;)
Bass integration is perfect and the sound completely natural.
Good luck! :)