Sometimes very similar fishes are difficult to positively ID. Careful study of one of our best Caribbean fish references -- the Reefnet DVD -- shows that even very experienced people get mixed up sometimes and use the same photo for two similar but different species. Also, marine fish ID is a relatively new science -- family and species re-classifications are constant.
My personal compromise for these similar-looking tube blennies -- applied only in Cozumel, where I dive most often and where there's under a dozen common species -- is: If it has two, clearly tree-branched cirri, it's a Secretary. If it has two little antennae -- OK to have a branch or two -- it's a Spinyhead. If it has a big bush on its head, it's a Roughhead. All others are discounted because I can't positively ID them. (There may even be some hybridization going on? Who knows?!)
You don't say where your photos were taken so there's no way to research which tube blennies live in those waters. You may get a better answer from a knowledgeable local -- I don't know. Depth is also a factor as some species are only found shallow. As you suggest, one or more of your blennies may be something other than the two species you're considering. Without great images, it's impossible to home in on the ID. IMO, with these you'll receive a lot of best guesses but you may not get to the point where you're absolutely, positively comfortable with any answer.
All Best,
Deb