Now that I've had my STG for a couple of weeks, a few questions have arrisen...

1.  On the bolt release  button, at the bottom it seems like it should be able to be used as a bolt hold open ala the AR15, but I cant seem to get the bolt to catch while pushing it in... if it is not a hold open, what is that for?

2.  Though I am a police firearms instructor, I can not figure out what would be the best way to execute a tactical reload, or hell a speed reload for that matter... anyone have any suggestions?

The bolt hold open is HK style with the charging handle. There is a groove at the rear of the movement, and you can give it the ol HK slap to release as well. I have not figured out how to make the bolt releae a hold open, I don't think it is designed with that in mind

I have been practicing for high seed tac reloads and I have not yet mastered the best way...

So far muscle memory has provided me with fast reloads by:
removing mag from pouch, placing between middle finger and ring finger, mag facing feed lips forward (toward muzzle),
using edge of thumb disengage mag release (with same hand)
use web of thumb to wrap mag and withdraw,
move hand over slightly insert mag, slap charging handle
place mag in dump pouch, iside shirt, cargo pocket or whereever you choose...

practice till fluid

I am open to suggestions as well as pointers as I am well schooled on AR's and M14's the Aug style weapons are a month new to me....

As far as the bolt hold open, the only way to manually do it is to use the charging handle as described above.  The bolt release that is mounted on the stock can only press down on the actual bolt catch (the one at the front of the hammer pack), not up.  Why that lower serrated pad is there on the bolt release is something I just don't know.

When I owned a STG I realized that it is not really a bolt catch, but rather a bolt release.  The bolt is held back when the last round is fired.  The only way to hold the bolt open is to insert an empty mag and pull the charging handle to lock the bolt back.  Remove the mag, insert loaded mag and push the bolt release.

Since the charging handle is non reciprocating, I did not get in the habit of HK charging slaps, I was told by MSAR that it was not good practice...YMMV.

Mag changes are awkward compared to the AR.  The best and quickest way for me in my duty rig:
1. Pull mag from pouch (left hand/mag from vest or hip, bullet tip forward).
2. Use left thumb to push mag release button.  
(This is were it get's funny),
3. Either use the base of the fresh mag to push down the empty out of the way of the mag funnel or grasp empty mag with pinky and/or index finger to pull empty mag out...index finger worked best for me.
4. Insert fresh mag and use left hand to push bolt release.
5. Back on target

Hope this helps for what it's worth.