Is this a hypothetical question using the figurative "you", or is this a personal question and you are looking for someone who can actually do it?
There is a big difference between counting outs and calculating probability. I do think this is a very important skill to develop. A player doesn't need to be able to calculate within 0.001%, but if you can consistently recognize your probability within +-5%, then you are on your way to being able to make very good decisions.
Equilab software actually has a training module for calculating probability to win (this is called
equity in equilab terms). This module will present you with a flop and your hole cards based on a range you specify and will then calculate your probability of winning based on a specified opponent range. I use this often as a way to sharpen my skills in this area. Do 10 or 20 of these a day for a week and you may see where you are misunderstanding how probabilities really get calculated. I actually keep a running total of my "training sessions" to make sure I am not losing a skill that I thought I had.
I think it will be very difficult to accurately/consistently) get within +-5% in your head, with the knowledge you already, without using software to tell you the number. Try it and see how you do. If you average +-10%, then this may be an area that a player should spend a little time on. A 10% error could really affect your ability to make good decisions because you are either overestimating your equity by a fair amount or overestimating your opponents equity by a fair amount.
Good luck.