Trig I would definitely suggest working three footers and 50 footers for speed. I would not mess with the ten, fifteen, etc... lengths during practice because of the above reasons.
Every nationwide or tour player I have worked with all say the same thing. When they win or have a great check they don't miss anything inside five feet. This means they are knocking in the short birdies and lagging the longer putts up there nice and snug.
To win a really big tournament, ball striking aside, all you need to do is make 99% of the short ones and then make three putts each day THAT YOU NORMALLY DON'T MAKE.
Also remember your mechanics.
Sustain your lag,
Trolio