I personally would not run MSten with Winny, but if you do, you should adjust the dosages so they work together bit without over doing it. Something like 20-30mg winny with 10mg of Msten. Curious to your reasoning behind wanting to use them both at the same time mid cycle?
Since you are running EQ, I'd assume your cycle is a bit longer, 16-20 weeks. So you could run the Msten or Winny for 3-4 weeks now, take a week or 2 break, and then run the other until the end of cycle. Or you could just run them back to back with no break. Just make sure to run proper supports.