Your in game map with "light radius" is great mush. What tools are you using?
FWIW, I can't recall precisely what DD4 says, but the original has light sources providing good illumination out some short way (15, 20ft, whatever) but then don't place any real limit on how far dim shapes/spaces can be made out beyond that. I guess this implies that you could see the vague shape/form of a large room/cavern even with a feeble light... but you'd only track/identify figures up close.
Also FWIW, I've been assuming pursuit turns take place at the (one-minute) combat timescale. Considering that flee/pursuit moves are right off the wargame table and happen in "combat turn" timescale there, it makes sense (to me) to continue this tradition in D&D. The other thing is, just look at the movement rates versus time scale! 10 minute turns makes pursuit speed
g-l-a-c-i-a-l whereas one minute turns makes pursuit speed vaguely plausible.
A couple of things to ponder maybe

[f=32]
Golgildir the Elf Medium (MV 12", AC 9, HD 1, hp 1/1, AL N) great cloak,
lantern; spells: color spray; scrolls: sleep, sleep, charm person
Hirelings: Georges;
torch[/f]
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