I like wearing two Mag-Volts in tandem but I still think you will need to shorten the silicone tube to get the proper fit.
I find that the fit is much tighter in the morning after wearing at night during sleep. There is a noticeable increase in the genital mass but I would not go so far as tp say an increase in testicle size. For me the effects of increase mass with more frequent nocturnal erections of harder constitution become less and less over a matter of days. For this reason, I generally alternate one week on and one week off.
Here is the video link to the demo video that shows how to replace the silicone tube but you will be able to see how to simply shorten the tube as well.