It depends on the aim of your work. Do you want to increase hardness, matte, gloss or something else? In case of increasing the hardness you may consider Lapramol 9000 (a blocked polyisocyanate by BASF) or short chain urea formaldehyde resins or dicyan diamide. So, please, specify the aims and the specification you want to reach.
The pot stability depends on the catalyst used. In case of tert. amines the pot life maybe not very long, i. e. one or two weeks, in case of certain organometallics it is extended to more than 90 days.
The mechanism is the cleavage of the end capping groups and a reaction of the liberated isocyanate groups with suitable reactive groups in the mixture. If there are only OH groups the water reaction may be a severly competing reaction so it is advisable to use some aminoalcohols as reaction components. But this is a question of formulating the system