Yes, Reminiscences is one of my all time favourites. I recommend getting Smitten's recent book: "Trade Like Jesse Livermore". This has more pearls of wisdom than any other book I know of.
Livermore did shoot himself with a balance of $10,000 in his will (he had however, previously placed some millions in what we would call irrevocable annuities for his wife and children). Unfortunately, he suffered from severe clinical depression which was not treatable in his day. So, in my view, the fact that Livermore died 'broke' does not detract from his amazing trading ability. He also had, at one stage accumulated a reputed fortune of $100m (and this back in the 1920s/30s)!
The £20k I mentioned is usually split into two trading accounts, 1 earning interest, the other not. Now that I think of it, I believe that over Christmas I had 25k in 1 trading account as I had some big (for me) positions on, however the margin requirement , as I recall was far less than this. I also have credit accounts with a number of SB firms and occasionally trade there but without depositing funds.
Strangely enough, I found that the single toughest thing to do was to sit on a large profit and resist the temptation to close my position. This, above all else, changed me from a 'go nowhere trader' to a profitable one.