I have been playing spades plus for the last couple of months. I became suspect after a short period of time. I also have emailed the makers with absolutely no response or indication or acknowledgment they received my email.
At this time I began keeping a spreadsheet that kept track of all cards dealt, scores and also a prediction of the outcome of each game. I was able to initially play 120 games of either regular spades or solo spades. After 120 games I was able to amass a 90+% prediction rate. I then played an additional 50 games with a 100% prediction rating.
With these kind of statistics I WOULD NOT recommend wasting your time or effort. This games is not based on skill, rather a slanted alogrithm that is calculated and determined before the game begins.
Neatandtidy about Spades Plus - Card Game, v2.8.4