Unfortunately I have no advice for suspensory support, but I am currently dealing with DSLD in one of my horses which was diagnosed last April. So I'll give some advice on how I've been dealing with that so far. First, I wanted to say that I'm sorry you and your horse are going through this. I personally know how tough it can be.
I've never heard of the ironclads suspensory support boots, but am curious about them too! I have heard of using SMB boots and while I could see them being beneficial to some extent, I don't think they would offer much support, and they would not be able to be used for a longer time. They may help a minuscule amount for more comfort during your trail ride though.
When I had a specialist down, he had recommended shoes with extended trailers to help support the ligament. Apparently, some of his clients have had a bit of success with them. I'm not sure the technicalities behind how that would work, but mabye someone else here would. I decided not to go with them though because the farriers that I've known in my area don't do well balanced trims to begin with and I also wasn't sure how my horse would fare by having to hold himself up in the back longer in order to put shoes on again.
One thing that did seem to help, at least for the short-term has been shock wave therapy; however, It is quite expensive to do as a frequent treatment here. The cheapest I could get it for was $176 CAD per leg (we did both hinds) and you need to do 3 treatments 2 weeks apart. The other thing that has helped a bit are the Back On Track quick wraps.
The biggest thing I've found that helps is being aware of the footing. Deep footing and even muddy or soft ground forces the suspensory ligament to work harder. Avoiding those types of footing can be a big challenge when it comes to maintenance, especially if you live in a wet climate.
Another thing you may want to look into is Dr. Kellon's recommended diet.