The Glenfarclas 105 is an excellent choice. You seem to be a little skeptical about this expression of Glenfarclas. I believe you will be pleasantly surprised with the 105. The 105 ( 60% ABV ) celebrated its 40th birthday in 2008 when John Grant released the 40-Year-Old Glenfarclas 105. The 105 was the first OB ( original bottling ) of cask strength single malt released in 1968 to the public for consumer purchase.
Released about 8 months ago, Glenfarclas released a limited edition ( 4000 bottles worldwide ) of 20-Year-Old Glenfarclas 105. Also an excellent dram.
Years ago, one taster described the 105 as, "it goes down singing hymns" I agree.
A word about calculating British Proof. Multiply the proof by 4, then divide by 7.[B] Using the 105 as an example, Multiply 105 ( the proof ) by 4 to get 420, then divide by 7; hence 60% ABV. [/B] Unlike the American proof system where one just takes half of the proof to get the %ABV.