Plastic Squeeze Condiment Bottles with Red Tip Cap 16-ounce Set of 6

what is the type of plastic; or what is the resin number on the bottom? pet, hdpe, ldpe, other?

How are people labeling or marking these to keep track of the contents? Can you write directly on the bottles?

Question can you use these to put craft paint in

Is it just me or do these bottles have extremely narrow tips making it difficult to dispense generous amounts of gravy?should i cut at the tip?