Hi. SLS is a terrible place to start - as is any online swinger match site - and it is particularly terrible for single men. The ratio of single men to couples and women looking for them is very much not in your favor, even if you have every other advantage. Since you're further hamstrung by having no photos (I really don't care what your excuse is, not having photos in a gallery that you open for anyone you message will pretty much guarantee that you will not do well, no matter what else you bring to the endeavor) and a less than engaging profile, I can't see your current circumstances changing much.
Others have touched on this, but I want to make it clearer. You say you've been interested in the lifestyle for years, but I don't think you truly understand it. Whatever we hope to get out of swinging, we also have to fill some sort of need for others. What need are you able to fill? Are you making it easy for people to choose you? Do you understand that this is not some sort of mecca of slutty women waiting to, yep, jump on your dick? That you actually have to work way harder than you would on a more evenly gender balanced site like Tinder?
I hope after the responses you get here, it's easier to see why a nice message that tries to emphasize that you're not creepy and that photos will be provided later (if you like, I can further explain why that's the worst thing you can do) isn't going to work 999 out of a thousand times.

