LOL prep for each worthy? HE is IMO good enough to fight each one by himself but add in prep and the seeker (idk much about her, I assume atleast herald level) he would crush each one.
I think the comic made a effort out of portraying HE not as particular powerful. I mean the HE wanted to avoid a direct confrontation with the Silver Surfer (atleast IIRC), and remember the HE only wanted a fraction of the Silver Surfers omniscience in order to locate Galactus elementary converter, he wasn't doing it to obtain power, that said with prep against each of the worthy I think he rapes them.
In the Iron Man/Thor the HE showed quite clearly imo, that if he has the significant prep. He can basically make Seeker into a being that counters each of the Worthy's powerset in turn.
As I said, KMC - High Intellect + unstated amount of prep = auto win.
I can't take Seeker seriously, she's basically a sort of Surfer-lite. Really lite.
No high feats and no real reservoir of power backing her up (no Galactus, just what HE stole from Surfer).
HE exapanded the power he got from surfer and seeker was only a fraction and on surfer level, even surfer said "the seeker is currently the most powerful being on the planet , she can make her thoughts reality"