Transfering of najasat

Dear brother as i have asked you that whether dry urine transfers when it come into contact with semen i had dry urine on my clothes and when i had a wet dream i woke up and checked the bed sheet and blanket but didnt see any wetness should i wash them. I doubt that it might have became dry or i didnt check properly. My mind says how didnt the wetness reach the bed sheet. But i checked and i didnt see any wetness and it gives me a hard time.

Also how about the cloth which might have semen and i have not washed if i have to wear it now should i wash them. I dont know which cloth have semen because most of the time my underwear has urine.

Also brother i heard that if urine is less than a circle inside the palm then if you dont wash it doesnt be considered najis. If that is the case then i am fine. But before i heard that it is one dhirm which is loke fifty pence here in england.

Here nearby there is no one to ask.

May Allah reward you, for your good work.!