You are making a common mistake among people who are somewhat new to re-entry. You place FAR too much importance on the specifics of the de-orbit. Even for a specific vessel, there is not a single specific answer. There is a range of possible answers. How diverse that range is depends on the vessel. A DG has a MUCH larger range than an Apollo capsule because the DG can produce more lift.
For instance, with a DGIV leaving the ISS, I can de-orbit above my target and land one orbit later. I can also de-orbit as close as 7M away from the target and still make a deadstick landing. There is NO perfect answer that will get you to the target - there is a range of answers that will allow you to hit the target. Whether or not a re-entry is successful (ie, safe and on-target) depends MUCH more on how you manage your energy AFTER you hit the atmosphere.
Urwumpe already mentioned "corridors". He also mentioned that there is a minimum altitude you can safely have at any given velocity (and the altitude increases with velocity). In a DGIV, coming in from the ISS, you will reach around 8 km/s velocity, and a DGIV can safely handle that velocity at altitudes above around 65k. So, for a DGIV, the re-entry corridor starts at around 65k. In a high AoA flight configuration (AoA 30 - 60) the DGIV creates enough drag that you can safely descend at around 80 m/s. In a low AoA configuration (15 degrees or less) you can't descend much faster than 15 m/s. This varies with the mass of the vessel - an empty vessel can descend faster than a fully loaded one (since it will loose velocity faster).
It doesn't matter how you get to that corridor - only that you enter it and stay inside of it. You can de-orbit early, and have a low ReA, or you can de-orbit later and have a higher ReA. As long as you can have the descent rate down to about 80 m/s by the time you are down to 65k altitude you will be fine. There is a limit based on the lift the vessel can produce. For instance, to de-orbit from a mere 7M from target, you will have to have a ReA of about 6.5 degrees (around -1000k PeA). Then you will set the AP to hold a 15 degree AoA until your VS is about 100 m/s, then increase the pitch to attain a steady descent of around 80 m/s (this usually means an AoA of 50 degrees or more initially to overcome the "bounce" and avoid climbing out of the Atmosphere). How much lift a vessel can produce (and it's current mass) determine how steep the ReA can be and still be able to pull out of the dive in time to avoid burning up. The more lift, the steeper the ReA.
So, the goal during the de-orbit burn isn't to hit the base - it's to hit the start of the re-entry corridor on a vector that allows you to remain in the corridor. This, of course, begs the questions "Where is the start of the re-entry corridor? And how big is it?"
The answer, of course, is that "it depends". Depends on the vessel's lift, drag, it's current mass, it's heat tolerance, etc. To calculate the corridor, we would need specific info on how the vessel calculates hull temps - and we don't have that. By watching the full-auto re-entry AP, we can see that the DGIV can handle an 80 m/s descent rate, and can also guesstimate an average decelleration rate. We know we have a max Vel of about 8k m/s at the start of the aerobrake, and use the average decelleration to calculate the time and distance traveled during the aerobrake. That tells us where the corridor starts. To use this with the MFD's, figure the distance traveled as an angular measure - not linear. Use this distance in the ANT setting.
The easiest way, of course, is a bit of trial and error. Start with an ANT of 45 (for winged vessels) and see what descent rate you need to reach the target. Then you can watch the hull temps - if the temps stay low you can decrease the ANT, if you have to reduce the descent rate to avoid burning than you need to increase the ANT.
Every re-entry will be a bit different. Different starting orbit, different fuel load, or different vessel entirely, etc. Once you grasp the concept, you'll be able to adjust for the variations without really needing to think about if.
The main point is to consider the re-entry as TWO separate stages. Like most space ops, plan from "last" to "first". Plan the second stage (the atmospheric stage, or ANT) first, depending on the vehicle. Then plan the de-orbit based on that target - and adjusted for the starting orbit. Keep in mind that EI (or ALT) is related to ReA. For instance, the DGIV specifies an ReA of 1.2 degrees based on the built in Flight Control Computer Display - which assumes an ALT of 120k. If you use a lower ALT you will need to reduce the ReA to hit the same corridor. I suggest picking an ALT and sticking with it - adjust the ReA but leave the ALT the same for all vessels (for that planet, at least). The standard for Earth is 120k, but you will probably get better results with a lower EI, the 80k that you are using is fine for LEO, but a bit low for higher orbits or lunar returns. I use 90km, which works for interplanetary returns as well.