Hopefully, someone can answer your questions better than I can, but I thought the following related information might be of some interest to you.
For questions about why we have newer insulins replacing older ones, like the Lente that worked well for you for 30 years (32 years for me), I would recommend a book called "Too Profitable to Cure" by Brent Hoadley, a Type 1 for 50+ years. I, too, think discontinuing Lente (and Ultra Lente) was a big mistake, not just for us, but for some guardians of diabetic dogs and cats who were not able to regulate their pets on any other insulin (see the links to another forum regarding this below). I now import my insulin from another country because neither Lantus nor Humulin N works well for me.
Lilly Humulin L - Visitor Opinion Post
Humulin U - Visitor Opinion Post
Humulin L Discontinued - Visitor Opinion Post
Discontinuing Humulin-U And Humulin-L Is Killing My Dog - Visitor Opinion Post