Timeout Directive

I have a situation where users can download very large files (1-1.5GB).
Locally there is no problem whatsoever however it seems that external users
run into the timeout directive is set with the default of 300 seconds.

The apache documentation states:

....
The TimeOut directive currently defines the amount of time Apache will wait
for three things:
1.. The total amount of time it takes to receive a GET request.
2.. The amount of time between receipt of TCP packets on a POST or PUT
request.
3.. The amount of time between ACKs on transmissions of TCP packets in
responses.
We plan on making these separately configurable at some point down the road.
The timer used to default to 1200 before 1.2, but has been lowered to 300
which is still far more than necessary in most situations. It is not set any
lower by default because there may still be odd places in the code where the
timer is not reset when a packet is sent.
....

The connection speed of the external user in question means that I would
have to have a timeout value of approx. 17,500 seconds @ 100KBs. My concerns
at setting the timeout this high is the effect on #2-3 above.

Is there any way to set the timout by file extension or alternatively by
directory? I wanted to test putting a different timout directive in the
directories but I am unable to test this at this time.

Any input would be appreciated.

TIA,
James