I can only offer my experience. I had a 110gm (20 to 25gms. normal) prostate removed and was continent very quickly, within a week actually.....8 times normal would be 160 gms or so, a new record in bragging rights here.
Again, it is really variable for each man and his particular set of circumstances with surgeons skill, his anatomy, rate of recovery and healing and so many more variables....
I found this part of the cite from lifeguyd interesting- concerning the reoccurance rate of PCA for men with greater than 75gm size. A little comfort for me...
Potency and continence rates were similar between the groups. CONCLUSIONS Prostate size at RRP does not affect the risk of impotence or incontinence afterward. A prostate of >75 g is associated with a lower likelihood of PSA-relapse, potentially as a result of lead-time bias. While an enlarged prostate may contraindicate other potentially curative cancer treatments, the outcomes of RRP appear to be unaffected.