I say put in 1 or 2 more years at the bank, stack up on that money, and then go for it. You always need more than you think you did when trading on your own. Let us know what you decide.
Are you a successful trader or not? Why are you asking this question if you ALREADY are a very successful trader. You should know if this is feasible or not from your current perspective.
I don't think you are. Are you trading completely on your own, using your own research and strategies without any input from the firm? My bet is that you execute trades for them, or somehow depend on them.... Anyhow, there is no point in changing curses with a winning team, so why bother?
Yes, 20% is a reasonable goal. But it may well take you a few years to get there. And what opportunities will you have you lost in banking during that time? And don't underestimate all the expenses you'll be taking on. A lot to consider. You have the luxury of time. Use it.
I have chatted with too many young traders who made money for a couple short years only to bomb when they go solo. Too often they specialized in areas that are either not feasible solo, retail fees increased, market been acting just right for whatever you been doing and changes, and inability to alter your methods. I would recommend to do longer term trading on side to make that 20% for min of three years to prove to yourself you can do it and continue to work as you have to bank more capital. Trading in any timeframe has ups/downs, so getting a steady 20% each year can not be counted on, some years it is whatever you do you can't lose and other years you fight to stay at breakeven and working many hours to do so. Education has much to do with the fighting years, more avenues to chip away at small but consistent profits might be all that is there for the year.
do you have a successful strategy that you can use at home,without the banks infrastructure and info?