I'm 20 years post op and I can tell you over time, your tissue changes to be like any regular old vag so you will stretch to accommodate any size penis or toy. As long as you dilate properly in the healing stage, you'll get good results.
I don't know how deep my vag is. I don't have my original set of stents from Montreal. I had marked them as I increased depth until I could take the biggest one all the way to the mark the doctor puts on it--and past his mark. After I got married, I ditched my stents thinking I'll never need them again, but a divorce and a new husband later, I had to purchase a new dilator. I haven't marked up the new one because it's so fancy lol...it's super fat on one end and thinner on the other and weighs a ton...I bought it from one of those approved online stores--can't remember the name. I just know because it's shaped different--kinda like a bowling pin(?) --I can't compare depth with the old stents because they were all straight, and non-weighted... I hope that makes some kind of sense?lol
Just trust that if you do the work, you'll get the results you want.