Lotta opinions here but apparently little experience with your particular equipment.
I have owned Wilson W/P 7's 20+ years - very similar to series 8 - so maybe I can help?
The titanium tweeter in this vintage of Wilson's IS a little hot and not as refined as more modern drivers. Despite this, these speakers still DO have merits at their current used values.
Not sure how well the Rowland amp you have matches the Wilson's.
I suggest trying a Pass Labs or, at lower cost, possibly a Parasound amp to drive the W/P 8's. What you are looking for is lots of current drive and a smooth top end to balance that tweeter.
I use my W/P 7's in a third system so didn't want to break the bank driving them. Ended up acquiring a used Parasound A21+. Turns out there is great synergy with a smoother top end and enough drive and transparency to enjoy these vintage speakers. I'm sure a Pass 250.8 would be even better but at double or triple the cost - so hey make your choice.
Remember the impedance curve of the W/P's dips to near 2 ohms below 100 hz, so the amp must be able to deliver lots of current. Some amps have a high wattage rating but are NOT at their best into such loads.
Hope this helps.
Good luck!