There are multiple programs for the use of midis. A listing can be found at The Silvis Woodshed. I can personally recommend "Melody Assistant. It is a shareware program that you can use to play a midi for free and will work on both a PC and a Mac. Instructions are given below

The program can be downloaded from http://www.myriad-online.com/en/products/melody.htm I just did it and put it on my laptop (ancient) and have run it without giving a license number.

You load the file via "import" (why import? because they are midi's and the program is made to write music. It treats the midi stuff just as if it might have been recorded from an electronic piano keyboard and converts it into the particular notes).

The tempo can be set from the "score" menu, set general tempo.

The start point can be set by (I think) right-clicking on the measure numbers at the top of the score and select "set reset start". (on the mac it is a control-click, I think that is equivalent to the right click).

Under windows -mixers, you can select small or large mixer. I use the large mixer, do the settings and then close the mixer window. It is very easy there to turn off/on a particular track. You can also set the level of the track. For example, my practice on the beginning turns all the instrumentation off and has the choir aahs the same. For movement 3, which I know less well, I have the other choral parts turned way down.

You can set the program to scroll the music as it plays. It can be done through the score menu and at least on my normal machine, through the preferences.

You can change tempo in different places in the program, set dynamics, etc. That is left as an exercise for the reader!