It wouldn't be worth doing if it was easy, that's for certain.
Pistol squats are the one other movement, aside from my pulls, that I train on a daily or near-daily basis. I have my sets and reps I perform on leg day, but ever other day I like to do 3-5 sets of singles on each leg just to stretch out. That's the beauty of it, besides maintaining flexibility in the ankles and whatever leg you're dropping down on, your opposite quad is
actively stretching to support your leg horizontally in front of you.
So how do you plan on progressing? I'd like to say I used some sort of deliberate mapped-out progression myself, but I tried to do a few one day, failed, waited six months to try again and succeeded spectacularly. The only variable in between was that my barbell squat went up. So, I'd suggest getting your barbell squat up if strength is the limiting factor, otherwise it's just a matter of finding your balance, in which the Convict Conditioning progression might be better or maybe the tutorial on Beastskills might be helpful as well:
One Legged Squat (The Pistol) - Beastskills