I'll try to circle back around after my market closes but for now just wanted jot down a thought on this.

Perhaps rather than looking at each trade individually you can look at each day individually or each week. In other words - rather than altering positions size based on your confidence in a given trade, you can alter position size during a particular day or particular week and then watch how your confidence levels change and how your confidence level impinges on your comfort level with the larger size. Once you can see more clearly how your level of confidence in yourself, your ability to have a positive expectancy, etc influences the comfort level with the larger size you can begin to isolate this factor (confidence) and work on it directly (perhaps by altering the ratio between how much charting and analysis you do vs. time you spend actively stalking trades). The idea would be to take the idea of confidence to the "next level up" - above individual trades to "you as a trader".

I do think that to become very successful you will need to recognize trades in which you have higher confidence vs lower confidence and "lever up" (as deucalion says) when you recognize a very good trade. But I also think this requires a high level of ability, confidence, and discipline to do properly.

Deucalion posted some Steenbarger docs about performance under uncertainty recently - here's a quote from one that is relevant (emphasis mine):

 Self-Efficacy – The athlete’s beliefs about his or her own capacity to perform is significantly related to actual performance. The belief in one’s own capacity to succeed is the single most important personality factor associated with athletic success. Studies find that interventions that improve self-efficacy tend to improve athletic performance, even when they involve mental practice (imagery) rather than actual athletic performance.