It is all down to the person you sell it to!
Some buyers may consider small coins over larger bars, some might not want to pay the extra money it costs to have the gold minted into coins.
Smaller coins have a largr premium but are more affordable!
If you can, try and get a mixture, if you just want to sell the gold back to the mint then just buy the lower premium bars, if you want to sell to collectors get the pretty limited edition coins and if you want to sell to stackers then just buy whatever you can at the best price.
Whatever you get you can't go wrong, unless the price of gold collapses, and then it wouldn't matter what you had (with the exception of numismatic coins which would hold their value)