Re: Sweet Treat Showdown discourages me from playing.

How?!!

I don't know. 

From my side the question is the opposite: I don't get why some players are never able to win the grand prize. Not even for a STS every now and then, when they like the prize a lot.

My strategy is this:

For 7 round challenges:

1st round: no sugarcube

2nd round: four sugar cubes

3rd round: six sugar cubes

For round 4, 5 and 6 I use 8 sugar cubes

I quit after level 6

For 9 or 10 round challenges:

1st round: no sugarcube

2nd round: no sugar cube if the starting percentage is 90%, otherwise two sugarcubes

3nd round: four sugar cubes

4rd round: six sugar cubes

For round 5, 6 and 7 I use 8 sugar cubes

I quit after level 7

The sugar cubes are 30 and with my strategy you would need 34 or 36. In fact I replace the sugar cubes with ads or simoleons, depending how lucky I am. Sometimes you get enough ads to increase the percentage. Sometimes I need to add simoleons.

Sometimes I fail: normally at round 1 with 85%, at round 2 with 89% or at rould 3 with 91-93%. But in general I play safe.

I use the cupcakes only for the challenges 9 or 10 rounds long and absolutely in combination with simoleons.

I use the cupcakes to buy extra sugar: 6 cupcakes for 12 extra sugar. In that challenge, I use simoleons to buy extra percentage every time that I find this possibility.

In this way I arrive to the maximum round and I make the best use of the cupcakes and simoleons. Because the royal tokens increase exponentially at every round. 

Normally I get the grand prize a couple of days before that the event expires.

I hope it can help.

Your strategy seems good but I no longer have access to the ads for help, so I forced to bail out every attempt.