1. We can't recommend a broker. I know members use TD Ameritrade, Tasty Trade, Interactive Brokers, and others, but we don't recommend a particular one.
2. It's hard to predict on absolute numbers like that because with Anchor it depends on how it got there. For instance, in your first scenario, if SPY increased by 25% at a steady rate of 2.5%, the strategy will absolutely crush the return of the index. You'll gain more than 25% from the leverage and probably make well more than needed on paying for the hedge. However, if you go up 15% in a month, resulting in rolling the hedge up immediately, then slowly lose 1-2% per month for six months (thus losing consistently on your shorts), then having a 20% jump in a month to get you to your up 25%, you may end up lagging a bit. You'd still be up on the year, but probably not 25%.
Generally in "smooth" up markets, this strategy is going to greatly outperform. In fast down markets its going to greatly outperform. "The worst" situation is choppy performance between +5% to -5%.
3. It's really hard to implement the strategy with less than $50k. That's simply because 3 contracts gets you close to that level. With $100k you can get a pretty good split on the short/long position. (So 7 long contracts and 3 short or whatever the math works out to be at the present moment). Once you get to the $140k or higher level, you can start looking at using the Diversified Leveraged Anchor (so adding in EFA, IWM, and/or QQQ).
4. The good time to invest is when volatility is low; of course it can be hard to predict what "low" is at any moment. Because of that we tend to price things based on cost of the hedge. We do that by taking the cost of the hedge divided by the amount of stock we currently control. Anything below 7.5% is good anything over 10% is "expensive." Yesterday when I entered some positions the cost was around 8.5% or so