I have one and I bought it without even holding one first. I like it a lot fits very comfortable. I don't believe you will need the cheek plate unless you want absolute perfect alignment with your scope. A lot of my friends didn't even need it when they fired my rifle.
The McMillan A5 looks awesome... i plan on getting one myself... probably on a 300 win mag. I would absolutly get it glass bedded... i dont see the piont of getting such a nice rifle and nice stock... and not glass bedding it. Personally i would not get the thumbwheel cheeck peice... i would get the adjustable saddle type cheeck peice with the 3 way adjustable butt system. Should look real nice on your 700P. Im curious... What caliber is your 700P? Ive always wanted to get a 700P in 300 Win Mag and put an A3 stock on it... but now i want the A5 stock on it... if yours is a 300 Win Mag plz let me know how it shoots.