You're gonna put on some nice size. I only went on sust for 8 weeks and it was amazing. PCT is key though because I know someone who ran it longer than me and lost about 60-70 percent of his gains because he decided not to run a proper PCT. I put on about a solid 15 pounds and lost about 8 of that in water the week I stopped, but I still had people telling me I was looking bigger while on PCT, you'll drop body fat too (if that's something you want), so it's definitely going to change the way you look if you do it correctly. Don't worry about the gains, that's going to come. Just make sure you listen to your body, even if you don't like what it's telling you.