Heck, if you're pulling the intake boots off the carbs anyways, you're already halfway there, just pull the carbs. There's no substitute for opening up the carbs and giving them a good soaking in a real parts cleaner. I bought a gallon paint-can sized parts cleaner at the local auto parts store (one of the big retail names, I forget which) and it has a basket in it, to soak the parts good. If you're careful, and just take your time, it's pretty easy and straightforward. Some tips:
Pick up a Service Manual 1st, the process is explained in easy, step-by-step instructions, with pictures for most stages.
Only pull apart one carb at a time. The jets are probably different sizes anyway, and you don't want to mix them up.
Let the parts soak for at least an hour. If you've got some good varnish built up, can take that long to soften it up. You can clean out other parts, like the coasting enrichener while you wait.
Don't put any plastic or rubber parts in the cleaner.
Use compressed air to blow the parts clean and dry. I cleaned my Virago's carbs without using the compressed air, just put them back together wet, and I don't think I got all the gunk out. I'll end up pulling them again to do the job right.
I tried the Seafoam, it worked a little. I tried spraying the carb cleaner right up the bowl drain. Made matters worse.
Good Luck with whatever you decide to do.