I have a Fluval C3 on a 25 gal long tank. It works well for the CPD's and Lamchop rasboras and shrimps I have in that tank.
A C4 is a bit more powerful obviously but on a 29 gal, don't think will be too bad at all, do remember you can adjust the flow output to suit using the filter intake postioning on the main body of the C4.
A C3 would be a bit too puny for a 29gal imho but it depends on the dimensions of the tank, if its a short 29G tank, then a C3 is probably ok but if its a standard or long 29g then personally I'd go with C4.
No such thing as too much filtration but there is such a thing as too much flow, as hobby5 already mentioned, it can depend on what specie of fish you plan to have as well as the tank set up.