Full Power.. | 2 Bars
Mobile | (Full-screen). | (Half-Screen)
==========================
Nak            77.00 | 59.37
Trico          77.90 | 62.47
Raon          79.00 | 65.74
Asate         79.00 | 65.74
Armor        79.50 | 67.11
Turtle         79.50 | 67.11
Mage         80.00 | 68.42
Lightning   80.50 | 69.69
Aduka        80.70 | 70.18
Ice             81.10 | 71.15
Boomer     81.20 | 71.39
JD              81.20 | 71.39
Grub          81.70 | 72.58

The originally posted formula is correct. There was no need for a correction.

Round off the angles as you see fit. (And no I did not calculate each mobile, I used Excel spreadsheet to calculate once, and copied the formula down the line...)

I've been using 72 2-bar for boomer to reach half-screen, so it's very close.