I would encourage you to go with the X30. I am about 7.3 BPEL, and still have plenty of space before maxing out on the X30 or Hercules. (And if you ever DO outgrow X30 or Hercules, you should go out and celebrate with a steak dinner, and be thrilled to have a need to spend more money on a larger device because your cock has grown so large! But trust me, it is most likely that the X30/Hercules size will be plenty for you for a helluva long time, maybe forever.)
In addition to the X30 and the Hercules, I also have the Penomet, which is much larger. When you are standing in the shower, and the device is larger than it needs to be, it is heavier and can lose suction more easily. So there is this advantage to not getting a model that is larger than necessary. This is the disadvantage for me with the Penomet, it is way larger than it needs to be for me, and therefore can be problematic sometimes in maintaining suction.
Also, by the way, I believe that the Hercules model at a lower price is a much better value than the X30, and I have both. The Hercules model actually works better and easier for me because it is simpler, and the modifications on the X30 don’t really improve function all that much, in my opinion. Having to mess with the valves is sometimes more of a nuisance than an advantage sometimes. The extra white collar/sleeve is nice, but not essential.
Another thing is, you don’t necessarily want to go for higher pressure than already available on the Hercules model. I have the X30 model that comes with the pump attachment, and I don’t use this attachment, as I have realized that more time is better than more pressure.
Not everyone will agree with me on this last point that added pressure is not advisable. So, if you have a Hercules model, and you wish to increase pressure, there is a simple trick where you use a device for removing air from wine bottle (“vacu vin” on amazon). This is described on goodlookingloser.com, if you are interested in further detail. But you don’t need to buy the most expensive Bathmate to get the pump, as this is do-able yourself, with a $10 device available on amazon.com. Instead of pulling air out of an open bottle of wine, you place the device on the end of your bathmate, and can then increase pressure little by little as desired.
Since I have three devices, I have some personal experience that may be worth considering, so that you don’t spend money unnecessarily. Most people will not out grow the smaller bathmate until they are somewhere over 8 inches BPEL, I would say.
Hope this helps!
7.8 x 5.4 (goal by November 1, 2020)