I think the problem with the 80s is that you started seeing the top 40 format fragment. Most "80s & More" stations around the country play essentially what KDMX has long done for its 80s midday show...female-friendly 80s hits that may or may not have been hits locally.
In the mid-80s, you had the start of the "churban" outlets (CHRs like KPWR in Los Angeles that played only R&B and dance). Billboard eventually started calling them "crossover" stations and by the late '80s had split the radio airplay into separate charts -- top 40, top 40/crossover, and top 40/rock. So, in '89, they had KHYI (the "Y95" on 94.9, for those that don't remember) in the first, KJMZ "100.3 Jamz" in the second, and KEGL in the last one.
In the fall of '86 when KHYI signed on, it was very dance and urban-leaning. Through most of the 1980s, KEGL had a rock lean (sometimes playing big pop hits from the likes of Madonna and sometimes not). KTKS was always mainstream until it became a virtual AC in the summer of 1987. During a brief period in the spring of 1987, those three got musically close as KHYI had recently gone mainstream and KTKS had not yet gone to AC. I found an aircheck of the 3 of them from middays in April 1987...
KHYI 94.9
Steve Winwood/The Finer Things
Starship/Nothing's Gonna Stop Us Now
Dead Or Alive/Brand New Lover
Cutting Crew/(I Just) Died In Your Arms
Psychedelic Furs/Heartbreak Beat
Eagles/I Can't Tell You Why
Full Force/Old Flames Never Die
Phil Collins/In Too Deep
Eurythmics/Missionary Man
Bruce Hornsby/Mandolin Rain
KEGL 97.1
Sammy Hagar/Winner Takes It All
Loverboy/Turn Me Loose
Lou Gramm/Midnight Blue
Chicago/If She Would Have Been Faithful
Huey Lewis & The News/I Know What I Like
Crowded House/Don't Dream It's Over
Talking Heads/Burning Down the House
Bob Seger/Old Time Rock & Roll
Psychedelic Furs/Heartbreak Beat
KTKS 106.1
Fleetwood MAc/Big Love
Aretha Franklin & George Michael/I Knew You Were Waiting (For Me)
Kim Wilde/You Keep Me Hangin' On
Hall & Oates/Maneater
Cutting Crew/(I Just) Died In Your Arms
John Waite/Missing You
Herb Albert with Janet Jackson/Diamonds
Boston/Cantcha Say (You Believe In Me)
Dead Or Alive/Brand New Lover
Huey Lewis & The News/If This Is It
...but that was short-lived. KTKS moved to AC and eventually died and became the original KOAI by fall. KHYI replaced it as the mainstream outlet. KEGL really went rock-leaning as those "40 minute non-stop Eagle free flights of back to back rock & roll hits" excluded a lot of pop and songs like Pink Floyd/Learning To Fly and Robert Plant/Tall Cool One that weren't big time singles on most top 40 stations were on KEGL (and I loved it...

).
Once KJMZ came on, you had almost no overlap between KEGL and KJMZ, as they had become the #1 and #2 "top 40" outlets here in 1989. KJMZ was almost all R&B music with some Paul Abdul, Madonna, and the odd Bee Gees/One single. Meanwhile, a 9/89 KEGL aircheck shows them playing nothing of that sort (night time "All Request & Dedication" show...I think today's teens have a little different taste in music):
Cure/Love Song
Van Halen/Feels So Good
Bad English/When I see You Smile
Fine Young Cannibals/Don't Look Back
Extreme/Mutha (Don't Wanna Go To School Today)
Tom Petty/I Won't Back Down
Midnight Oil/Beds Are Burning
Tubes/She's A Beauty
Love & Rockets/So Alive
Sammy Hager/I Can't Drive 55
Warrant/Heaven
About the only song I remember KEGL and KJMZ having in common at the time was KEGL playing Peter Schilling/Different Story (World of Lust & Crime) regularly for a little while and KJMZ having a 12" mix of it during its 10PM "Thunderstorm" mix show a couple of times.
So, if you are building a playlist for an 80s format based on the market, what's the top 40 station you use here? KEGL was #1 for most of the decade. Probably an Eagle listener didn't spend much time listening to 100.3 Jamz and vice versa.
It's not that Dallas was unique...even Wichita Falls had a similar set-up. By the late 80s, KKQV "QV103" had gone dance and R&B; rival KNIN went the other way as "Rockin' 92-9." KNIN went more mainstream after KKQV gave up and went oldies. The market is fragmented again today as the two stations that call themselves top 40s aren't...KNIN is a hot AC and KQXC "Hot 103.9" is all hip hop and R&B music. In the late 80s San Antonio, KITY "Power 93" and KTFM "Hot KTFM 103" were dance/R&B while KSAQ "Q96" was alternating between mainstream top 40 and a top 40/modern hybrid. At times, Q96 had almost nothing in common musically with KITY and KTFM.
For whoever tries a 90s oldies format someday, you have the same issue. The format really faded in the early 90s with large number of outlets moving to the new hot AC format. In a few markets, the CHRs went the rock/CHR route (KKYK Little Rock, KTUX Shreveport, KMYZ Tulsa, KEGL here again in 1992 after being mainstream 1990-1992). Most of those either went to full time AOR or modern outlets after a while. The modern rock format finally came to most markets. By the mid-90s, you had the format come back in numbers. But what is the music you select...most of the early 90s "hits" were of the Jude Cole/Baby It's Tonight and Bad Company/If You Needed Somebody variety for the stations that went more adult or all the Nirvana songs for stations that went the rock or modern route. By the late 90s, hip hop took over much of the top 40 playlist. Most of the folks that liked that probably aren't going to like what passed for top 40 of the early and mid 90s...