The technique is interesting, and fast. If you weigh your isomalt before melting it in the microwave and than microwave it to liquid, add 5-10% water after letting it stand a minute or two.
Be careful and add it slowly as it will spit and sputter. DO NOT add it all at once as the water can go in and under the sugar, heat instantly into steam and explode the hot isomalt all over.
The colouring process is fine, but I would add the colouring to the water youre going to add and strain it well.
I usually prepare large amounts of sugar or isomalt and than let it harden 5kg or more at a time. I break up the slab and keep it in zip-lock bags in an airtight container with silica gel. When I need it I just pop it in the microwave and its already balanced with the water etc. Be aware though the more you microwave the isomalt and sugar the harder it will get to use. You are cooking out the moisture every time it gets liquid at all. After a few trips thru the microwave you may need to re-hydrate it. Weigh the isomalt, melt it, and add 5-10% of water to it again. Youll notice a big difference. You can go as high as 20% but after that it starts to affect the stability of the finished piece.
Nice pictures in the photo album.
How long was the course?