I use mostly rice starch paste for new binds, and JinShofu wheat starch paste for repairs.
Because I am soooo impatient with cooking up the paste by hand on the stove, I succumbed - 
it's time to experiment with the 'new-fangled' microwave.

I tried (as you can see by the pics) initially to replace the standard stove-top measurements I am now used to with an approximation by way of a handy handout I received. I did find, however, that the resulting paste was not able to be cooked for long enough for good 'tack' because it was quite thick to begin with.

Hmmm back to the drawing board.

After much messy experimenting, it turns out that the best 'smidge' measurements for me are:
(to make just enough paste for one session, so I don't have to store or waste it)

BASIC RATIO is 1:4, powder to water
I used 1 teaspoon starch powder, mixed into 4 teaspoons purified, deionised water 
in a glass smidge-bowl

In my microwave (1100W), it cooks in 10 second bursts at normal 100% power,
take out and stir after each burst.
It'll be very thin and cloudy at first, but then thicken and become translucent. 
About 4 bursts of 10 sec should do it.
(of course, everyone's tack preference and microwave doo-dad will be slightly different)
Test tack between your fingers - if it's right, it should really resist you pulling fingers apart
 (I never did do this bit right til I was put straight by the talented Ms Karen Vidler, 
from Book Conservation Services - Thanks, V.  x)

Just enough for one session, 
which is great when you can never be sure if family life will fit into your bindery schedule.

Give it a crack :)
(oh, and you can use this method with store-bought rice starch, 
for use on regular home projects,
but the times and ratio might need tweaking)