Quickload,
https://www.neconos.com/ , is a wonderful tool for playing what if. What if I seated this bullet deeper, what would the pressure change be? The answers are there at just the click of a button. Quickload is not a substitute for a loading manual, but if there isn't any load data for what you want to do, then it will get you close. Your next best reloading friend is a chronograph. Velocity doesn't come for free, you either have to burn more powder, or raise the pressure. So if your velocities are similar to what Quickload has predicted, then you can assume that the pressure should be similar also. But if your velocity is higher than predicted, then the pressure will probably be higher also.
Quickload is a little pricey at $152.95, but it is such a wonderful tool. I bought my copy many years ago when it came on a floppy disc, so I have only had to pay for the upgrade version to stay current.
If you reload alot, or like to stray from the beaten path, then it is money well spent. You can select any cartridge, bullet and powder combination and see what would happen.
They will even let you download a demo copy to play with for free. I think that it only has the 300 win mag in it, but it will give you an idea of what to expect.
https://www.neconos.com/details3.htm
Now with all of that out of the way, if you have any specific bullets that you want to seat flush, I'd be more than happy to plug the numbers into Quickload to give you an idea of where to start.
What I will need is the bullet length, the seated length, powders you are interested in and the barrel length of your firearm.
Glenn.