the fact that you are using the same transformer for the track power and the switch power definitely simplifies things. You can skip the part about checking the voltages with track power at 0V and then above 0V. That step is only necessary to ensure that two separate transformers are phased correctly. In your case, if it is functional, then you should be set.
Ace does have a valid point regarding the switch contacts. You may not get 25 years of functionality out of these controllers, but they should work for sometime. On my current layout, I am using some very small momentary switches and I haven't had any fail yet.
It will definitely be impacted by the number of times you activate the switch.
Keep us posted on how things work out.