Hi.. I am not sure about T205s... but with T206s.. it is rarer to have a "true" ghost on the front than the back...
I say a "true ghost" because... many people consider a double exposure a ghost... double exposures... are where the same player appears twice on a card
This double exposure. will increase the value of a $40 card to $400-$500.
A double exposure is not a true ghost.
"a true ghost" on the front will have a different player shown from the player who the card is of. This will jump the value sky high... a black more detailed ghost will be more expensive than a color version which is more of a Silhouette. See examples below:
color front ghost. Silhouette style
Black ink (more Detailed) front ghost.. very rare..
Ghosts on the back... commonly get confused with wet sheet transfers.. wet sheet transfers do not increase the value in my opinion.... a true ghost on the back will have the border of the card.. and is usually the same player as is on the front... value is also very high on these.
notice the border on the bottom of the weimer (the chance above has it as well)
Then there are ghosts that have multiple errors with them... like multiprint backs.. or split backs.. or upside down backs... along with the ghosts...
This also is extremely rare.. and value is sky high
Hope this is helpful