Taller why do you say you could lenghten to 193-5CM?
I'm as tall as you and I want to lenghten 6CM in my femurs, I almost think that's a stretch actually since a lot of doctors state that 5CM should be the limit.
Also, I can't speak for you but my legs start to look really long after a 7-8CM increase, and my arms start to look quite short after I've added 9-10CM. If I lenghtened 10CM I would look strange in thick boots I think.
I say so because I've made mockups in which I don't look obviously disproportionate at 192CM. If I did arm lengthening, I'm sure I'd be fine, proportionally. I don't care how I look in the thickest of boots after LL. I wear converse-type shoes and thin boots most of the time anyways, and if I look a little disproportionate the few times I have to wear super thick boots, I doubt anyone would take enough time out of their busy lives to carefully scritinize my proportions and notice. If people did somehow notice legs being a little too long for height, how much do you actually expect them to care? Proportions vary a lot naturally anyways, as you can see here:
For example, I am your height, am probably pretty close to your age, and yet my arm span is 185 or 186 CM while yours is 175CM. Your sitting height might be a little more than mine of 96CM, who knows, and who really cares that much, as long as it falls into the natural range for your new height? One guy who lives next to me is 188CM tall, has a lower sitting height than mine, has the same arm length as me, but has much longer femurs. I got him to throughly compare proportions with me. I could post a photo of you want. Meanwhile, my father has much longer arms at 188CM. Neither of them look disproportionate in any kind of footwear. I used to care a ton about proportions, as you do now, but the more people I compare myself to, the less I care, because there is so much variation out there. You even stated that your 190+CM uncle has almost the same sitting height as you. I have 193CM uncles with much, much higher sitting heights and wingspans than me. There is so much variety in nature.
My point was that, because of my high starting height, I could theoretically exceed 190CM through LL, and yet I have no desire to. I just want to get to a point at which I can be proud of my height and not feel short among my male family members who are 188CM plus. I could live a good and happy life without LL, but height insecurities would perpetually be in the back of my mind. I have to decide if the risks are worth it, but in recent months I've proven to myself that I can still be quite successful and happy at my current height.
I agree that lengthening too much is a terrible idea. Ideally, I'd do 4CM on the tibae and 5CM on the femurs, but given that LL is so hard, I'd be happy with 7CM on the femurs as well, which isn't far from your goal of 6.5CM. Hypothetically, if I did 6.5 femurs and 6 tibiae, both safe lengths, I'd easily be 190 barefoot, but again I don't care that much about the numbers and won't pass 190.
I own Bugarri Lorenzo elevator shoes that I sometimes wear to clubs and bars for fun. They add 12CM, making me 190. I look fine and got lots of positive attention in them, deposits the fact that my arms appear a bit short at that height. In the real world, few people care, and the benefits of the height far outweigh the harms of slight disproportion.