Sounds like this thread should be in the Ergonomics section rather than here.
First off, some basic ergonomic tips: Your desk surface should be low and chair high so your elbows are at about 90 or even slightly more when resting your fingers on the board. If you can support your elbows on the chair somehow that will help, too.
The keyboard should be at the correct angle. Don't raise the back edge as that forces the wrists to bend upwards. I find most boards have a good angle when used "flat", but some are too angled, the HHKB has a good angle when not using the flip out feet. Raise your hands when typing and only rest the nub of the palms on a rest that has the correct height when you're not actively typing. A lot of mechanical boards are higher in general than RD boards and benefit from a tallish solid palm rest.
The Razer Lycosa has flat profile caps and very short key travel, so it's not "normal". The travel on Topre and MX switches is quite similar to most "normal" rubber dome boards with contoured keycap profile and a whole lot better than original mechanical typewriter keys
Mechanical keyboard contoured keycap profiles are designed to help alleviate the stress of stretching your fingers out to different row keys, but the fingers need to be in the right position and at the right angle for it to help.
If your desk setup is good, angles are fine and your wrists and fingers are in the correct position and you still get fatigued using the board, it could be that you either simply need time to get used to the keycap profile and travel or that you really do need to shorten the travel a little. The dental band mod is a nice one, IMHO, it improves the key release sound a lot. Not sure about the actual key travel reduction.
