Beyond feel &amp; experience, is there a rule conductors use for ritardando in terms of  (a) its rate, (b) its change in rate, and/or (c) the relationship between the final tempo and the tempo of the piece?

(In getting my software to execute a ritardando, I employed over four measures a measure-by-measure decrease in tempo, and what sounded "right" to me ultimately was decreasing the tempo by 4 bpm, then a further 9, then a further 16 (pleasing pattern) to arrive at 127/156 (close to 3/4) the original tempo.)




Question: How do you decide what to get first, Forge or Twilight Council?
Answer: You shouldn't be thinking "I get some troopers and some upgrades.".

Base yourself on what you need to do and what is the best to perform than situation. If you play defensive you probably want more Sentries to block the ramp, while if you play aggressive you want the right mix of Zealots of Sentries based on what you are up against. Sorean outlined some...

Let's suppose you are not planning on early DTs (cheese) or HTs (later game units)...

For defensive play, it makes sense to start of with a Forge and +1 Armor; also, cannons.

For aggresive play, your should have an intention. Denying an expansion, taking down supply or even having the chance to win the game are possible choices. In most cases you would probably go for a Forge and either get +1 Attack or +1 Armor first based on the situation. You should get an idea how a certain upgrade affects your units againt other Tier 1 units; for example, in PvZ the +1 Attack helps a Zealot to kill a Zergling in 2 hits instead of 3. Sorean outlined more...

There aren't much cases where you would go Twilight instead, one that would make sense is when you planned on blinking inside the main using an observer. However, you shouldn't be getting blink because you can blink your Stalkers back easily because it will go at the cost of their HP / Damage. Your intention is to do as much damage while losing the least of your units in that early push...

You should be thinking "I'm going to attack/defend this way, using these units/upgrade(s)."

The other upgrades can follow up while you expand simultaneously, 'cause that gives you the edge...
Update, might not be relevantt: Please note that the cost of several Forge updates have been decreased in the latest patch!