For someone who has never used tube callers, it looks like you hit the mother lode....
If you put your time in practice with a tube caller and become proficient with it, a tube caller is deadly. Recording yourself with a digital recorder for immediate feedback works well. Also, getting the right thickness of latex for your tube caller is critical for speeding up the learning curve. Trojan non-lubricated would be my recommendation for a start...but be sure you prepare the wife or girlfriend before they find your stash.....