Hello,I've got a large experience with SharePoint Workflows and Nintex Workflows as well. And I can use K2 workflows as well.
Which one of those are you using? is this workflow already made and needing adjustments/tuning? if so could you send a print-screen of it?
ASP.NET, JavaScript and HMTL are also some skills that I got experience.
Looking forward to hear from you,
André Alves.