Pick one or the other.
What criteria are we to use?
There’s only two criteria that apply.
preference
Both of them are 68. Are you really sure their breasts are the best criterion at this point?
I pick Bailey. 
Ditto.
While I would’ve kicked neither one (in their prime) out of my bed for eating crackers, neither are they my ‘style’, even though I normally prefer buxom women (not a deal-breaker, just a tie-breaker). Both struck me as too high maintenance (not that I ever knew much of them beyond their roles as country singer and WKRP secretary). That said, Loni was a little more appealing to me, but not by much.
ETA:
More appealing than the two choices combined.
Fight to the death it is.
No Quarter given.
We’ll I’ve heard of Dolly Parton, so I guess I prefer her.
My man! I thought I was the only one with any taste here. 
It’s an impossible choice. I’ve never found Loni Anderson to be attractive, and I’d have to shoot Dolly Parton if she started singing Country to me.
In their prime? Loni by a mile. Some of the more…formative events of my early teenage years happened while WKRP was on…
Bailey.
Yep.
Mary Ann.
It’s difficult because they’ve both always been essentially drag show imitations of themselves, but here’s young Dolly Parton vs. young Loni Anderson.
But here’s young Bailey Quarters!
I dunno. I’ve never heard Loni Anderson sing.
It doesn’t matter. The answer is Dolly Parton.
She knows how to whistle though. Just put your lips together and blow.