Lately I unboxed and put the Rabaconda Street Bike Changer together, watched the company's videos, and wrote out my own numbered procedure.
It is 89°F out and extremely humid. I put the wheels and new tires in the sun and then worked in the sun.
It seemed logical to learn on the smaller front wheel first. I dismounted the tire. That was easy. Breaking the bead on each side only had to happen in one spot. The rest of the diameter easily pulled away. I installed a 90° valve stem. My torque wrench, I thought was going a bit far. So I tested it in the garage. It was only clicking on 20-30 in-lbs but at 84 was not breaking. (How to loosen it after sitting unused?) I tightened the nut and twisted the valve. I figured that my gauge would be if I could rotate the valve it was too loose. So I tightened the nut just to the point where the valve stopped rotating with moderate force. Let us call that exactly 7.4 ft-lbs. Thoughts?
Mounting the tire the first time it got too taut. I heard a little cracking. I used a mallet to back it out from where it was stuck. I found a few rubber shavings in the tire. The next attempt I made sure to (follow the darn instructions) keep using my hands to push the tire into the drop center giving the mounting portion plenty of give. It then mounted easily.
Generating a little sound of crackling, did I damage the cords in the sidewall folding it over too aggressively?
I was not outside a long time but it is miserable out, so that is it for today.
Perhaps I will continue with the rear wheel tomorrow. It is going to get cooler out. Hopefully the sun will shine which will still heat up everything adequately.
I think that the valve stem is fine.
I stopped torquing 90° valve stems a long time ago, as the 7.4" lbs always let me turn the stem...which is no good, so now I just snug them...basically what you did.
As for the Rabaconda Street, after changing over a dozen tires on it...it has really lost it's appeal to me...and I no longet recommend it to anyone...I even emailed Rabaconda.
It gets the job done...but is nowhere near what it is made out to be, a pretty effortless tire machine...which it is Not.
If it was $200, sure, it works better than any manual changer out there, but for $800...it's not even close to being worth it, as for a grand I can buy a new hydraulic/electric changer.
Some tires go on easier than others, as some go right on...and others seem nearly impossible, no matter what manual method you use, regardless, every tire I've mounted with the Rabaconda street has fought me.
I thought that it would get easier with some practice, but not so.
If you don't have room for an actual electronic tire changer, or need to change tires trackside or anywhere without electricity, then fine, otherwise, this thing is way overpriced and takes too much effort.
Again, it does the job, but I apologize for ever recommending it.
I hope that the other tire goes on well for you.
As for damaging the tire on install, if it's holding air you're fine.