moving decimal point

[Rongit53]

I use the dtostrf function to convert a float variable into a string. When outputting the string with tft.drawString, the decimal point jumps a few pixels to the left when changing from two-digit to one-digit values. I think this is caused by the smaller pixel width of the space compared to the pixel width of the digits.
Where can I see the fond used and how can I change the pixel width of the space character?