I think you may be stuck with your "F" sign which is a "K" sign in ASL without a BOLD for a while. If it were the Brazilian "F" (check the Brazilian sign puddle), the thumb and index can each be bolded, else you have to construct the sign for clarity. Is there another sign with the thumb, forefinger, and middle finger with the thumb underneath the index? If not, then you may have to live with it for a while. No need to bold the thumb unless this isn't enough.
= this has the thumb under the middle finger.
= this has the thumb on top of the middle finger.
I wrote the sign for "F" but it *seems* the thumb should be "bold".
Should it? And for the "T" the index should be bold. I don't know how
to get those in SignPuddle. I have attached the drawing for