Recommendations on a 22 - 26 ft weekender?
With regards to your questions about Grampians the answer very much depends on the model. The Grampian Classic 22 and the Grampian Classic 31''s were very nice boats. The Classic 22 was a very nice, light weight daysailor/overnighter designed by C&C. I actually owned one and really thought these were fun boats to sail. They were reasonably well built and fairly inexpensive but not particularly "heavy or comfortable". The Classic 31''s were heavier more traditional VanDyne designs and were also very nice boats. They come up for sail at pretty reasonable prices from time to time.
At some point in the late 1960''s Grampian totally retooled its line coming out with the Grampian 23, 26 and 30. These were not very good boats and I would say that with the posible exception of being inexpensive they would not meet any of your desired criteria,"Heavy, well built, comfortable, inexpensive, and fun to sail". They were pretty much value oriented boats with mediocre designs and pretty shoddy workmanship.