[Closed] Training log - rating difficulty of rides with data

I've kept a training log for a few years, and I'd like to rate my coming rides for difficulty. I want to anticipate how difficult unseen rides may be (a 150 mile offroad ride - 'really difficult', yeah yeah) as I map them on something like bikehike.co.uk.

I can't allow for things that I realise genuinely make things tougher/easier like dry ground vs. wet ground, rocky and rooty vs. smooth, wind conditions, amount of breakfast eaten, so I'm thinking I'll be using the distance/ascent numbers that are easily to hand.

I realise that this may fall on deaf ears but someone might be able to help me start to apply some kind of basic rules of difficulty to unseen mapped rides.

If I can also introduce time taken as a factor, that would be interesting.

I've found the formula that the TdF uses for its climbs:

(H/D*100)*4 + H²/D + D/1000

where H equals Height Gain, D equals Distance. I've applied this to some past rides and it's giving me some interesting ratings on the following efforts:

marshbrook marathon 2011, RATING 167 MILES 44 ASCENT M 2500
mayhem 2010 - 7 laps, RATING 143 MILES 62 ASCENT M 2772
marshbrook marathon 2012, RATING 97 MILES 45 ASCENT M 1900
Forest Hard climbs, RATING 65 MILES 17 ASCENT M 871
road ludlow - newport, pembs 2010, RATING 60 MILES 131 ASCENT M 2614
road ludlow telford ludlow 2012, RATING 28 MILES 64 ASCENT M 1144

I know how I felt during those rides because I've kept a record. And I know that the triple figure ratings are way way harder than the low double figure ratings.

So if there's anyone out there who is a number cruncher, I'd be interested to get some tips.