You are certainly obliged to stick with what you consider more comfortable.
But if you do mess with these short races , then it can only be a learning curve for you and you will receive great benefit , although I would suggest as a financial proposition , you keep away.
In fact it prolly be to your favour if you keep away completely from the fincial arena until you know the animals as well as I do.
Even I have very little feel for it , but every day in every way I am getting better and better.

Regarding So Manic.
If you notice the FormLines about this animal , it usually runs really well , or it runs totally dismally.
Its a matter of perks and quirks of individual animals.
Look at the Boxes the animal rates poorly on.
They are always wide Boxes.
It just seems very uncomfortable out there.
If you download one of the WatchDog FormGuides , yoy will find the Box Statistivs for each animal.
I choose to use The Rocket Scientist.

Here is So Manic Statistics.
Box 1 is 7 starts for 4 wins and 3 4ths.

Much of the animals failures are from wide boxes and in town.
Theses Form Lines need to dismissed from your calculations and you will find a much higher assessment of So Manic than you originally had.