I think you're talking about a watermark and embed code rather than actually putting text onto the video iteself, because that's really the only way to make it clickable. Unfortunately, a lot of people will remove this when they copy/paste your embed code, and others will just rip the video entirely, which also loses your branding. That's why I offer this service.

I never have a problem with any spacer on the right. I just make my images the same width as the video so that I do not have this problem. I know that vshare displays as 425x350, but you pretty much have to ignore that and go by what the original video size is.