So, you taped it up and give it 24-36 hours.. if the vascular tissue is too damaged, the leaves won't perk back up and you'll know it's unlikely for it to heal. I don't know the exact time range you should give it. When i accidentally do this, sometimes they don't even wilt initially, but others do and are perky by the time i look in the tent the next day after being taped up. After it heals, remove that tape so you don't restrict growth. Best to use tape you can easily remove. fold over an end so you have a flap to grab and pull.
just add the potassium silicate to your fertilized water.. adding a second batch of water with 15ppm silicate only on top of what you just added reduces concentration of what you added just before.... this is counterintuitive. can you find a balance doing it that way? sure, but it's a needless learning curve / wasted time and effort to do so. Or, if you are adding inbetween irrigations that's just not a good practice either.. screwing with the concenetration you chose with your fertilizer formula... "counterintuitive" and doesn't matter if some anecdotal nonsense says it can work.. of course it can work, but it's 100% unnecessary to adjust to the repercussions, if any.
Silica supposed to help in a measurable way, i just don't know the magnitude of its benefit. I've never bothered. e.g. blue wavelengths promote more branching but if it's only 5% more who gives a fuck? am i right? lol.. it is a measurable effect, but that doesn't mean it's very useful or can cause drastic change. I made up the 5% to prove a point, and from what i've seen with 1/2 2900K (warmer, more reds) and 3400K (cooler, more blues), lanky plants are still lanky plants and bushy plants are still bushy plants. there is no drastic effect. I'd be surprised if it's a 5% difference in branching / vertical growth due to blue vs red proportions of light of a typical grow light, i.e. common sense applied to range of light characteristics. I do not doubt it has a statistically significant effect, it's just plain to see it is a very small effect and really shouldn't influence which light you buy vs total power (umol/s PAR and/or ePAR).
The 'brittleness' occurs no matter what.. Branches get rigid (think the term is ligorous? there's a fancy vocabular term for this process) after a short time and become more difficult to bend and more likely to snap. Does silica hasten this? maybe? it is supposed to help with stronger branches, so that's a reasonable extrapolation if you don't have better source material to reference on it. beleive bruce bugbee (youtube) has some good info on silica.
don't trust info from a forum or grow questions unless it is backed by some proper source material. Anecdotes are often a misunderstanding of reality. take whatever you are told here and go do some googling, reading, watching.. paint a fuller picture. avoid the purely anecdotal nonsense.