My opinion is that you should not try to define "reasonable" or put it in a box. Because I'd say 100% of your definition of that comes from what the media reports, and that is definitely wrong (or at least limiting).

Instead, keep an open mind, a clean slate. My personal intention is to just see what shakes out and learn along the way. Perhaps you will find that your definition of "reasonable" is some combination of high profit factor and low drawdown. You'll probably get a sense for it over time.

One use of OptimalF that I am exploring, that I think should be "ok", is for the purpose ONLY of knowing which pairs/algos/directions to trade. In other words, let your backtest run all variations of pairs/algos/directions and then based on OptimalF, trade only those proven profitable... but do not apply the OptF factor to the trade weight.

In other words... test every combination, but only keep the ones that show any profitability at all. Still test only with minimum flat lots.

Depending on your strategy, my guess is that some assets will show "excellent" performance while others will seem only "mediocre". However, OptimalF does know best... so once you find the cream-of-crop, you can then apply OptimalF to maximize your bang-for-buck.