You need the best home 02 concentrator to get a decent flow rate of oxygen. Remember, the chamber when pressurized will slow the flow down anyway. And your mask will be leaky, so you'll lose 02 that way, also. And 02 concentrators are not 100%, at best around 80-90%. So, you need a good flow rate and a used Integra is a good buy and very reliable.
Re: hardchamber vs softchamber for lyme. I didn't know about softchambers when I did the hardchamber. There is no comparison, the hardchamber goes to a much deeper pressure, gets a lot more 02 into the tissues, and is 100% 02. On the other hand, you can't do hardchambers forever. I don't think it would be healthy to have that much 02 all the time. And it's exorbitant. I mean, theoretically, you could purchase a hardchamber for home for $50,000 and some folks have.
But anyway, if I knew then what I knew now, I'd do 2-3 months in a hardchamber, really getting the lyme way down (and it does--there have been experiments in guinea pigs where they built little hardchambers for them, and it did make all the spirochetes go latent. But within 3 months they were back). And there's the rub. So then I'd switch to softchamber at home to keep the "terrain" hostile to the buggies.
But it seems some respond really well to hbot and others not so much. Those others, perhaps their issues are more viral. In any case, I always recommend a trial if you can, at a doc's, to be sure you're a responder. If you are, a trusty used home chamber can be one of the best tools for healing.