Still messing

Ok. Since I last wrote I have learned a lot. I reach a MHR of 180 on Monday (1 mile w/u; 3 min bursts of all-out speed with jogging returns between; 1 mile c/d). I have seen higher readings in the last two weeks. On one occasion, I had a reading of 186 and on others 184 (at least twice) and frequently 182.  I did have tired leg muscles on Monday, so I decided that I should probably add a few beats to that MHR (a sort of compromise between 186 and 180) giving me 183. I then adjusted my HR on the Garmin giving me 5 zones starting with zone 1 which is aerobic, zone 2 which is long/medium long and so on. I am using the percentages as outlined by Pfitzinger and Douglas on p.19 of their book Advanced Marathoning.
My training zones then are:
Recovery , < 76% = <139 bpm
Aerobic, 70-81% = 128 - 148 bpm
Long/Medium long, 74-84% = 135-154 bpm
Marathon Pace, 79-88% = 144-161 bpm
Lactate Threshold,  82-91% =150-166 bpm
Vo2 Max, 93-95% - 170 - 174 bpm
I did try taking my Resting Heart Rate once, by leaving the monitor on all night, and got an average of 56. There were lots of spikes in the reading, but it did go as low as 50 at one stage. I will return to that again.
So, using those figures and with the sole purpose of 'conditioning' or 'building miles' or 'base training' at least until May/June, I am committed to 5 runs a week for the next 3 to 4 weeks plus one cross-training. I will also attempt (as opposed to commit to) a 6th run. I hope when the mornings are brighter to commit to 6, maybe 7 runs, a week. I also want to build relatively gradually, although I  know that I could do more frequent runs with less mileage too. Taking the light/work situation into consideration, the 5 runs (possibly 6) will see me into mid/late February. I should add that I am starting from a comfortable average of 20-25 miles a week, although have done more than this (and less too) in the last year.
I have also read another interesting idea in the Lydiard stuff online ... the idea of running to time rather than distance.  I tried that today and thought I might try that for the rest of the week, with the exception of the long run at the weekend. Alternating 40 minute sessions with 60 minutes sessions (the ideal is 60/90 minutes sessions) and keeping it slow, using only Aerobic and Long/Medium long pace for now, I will try the following:
Wednesday 40 minutes @ aerobic
Thursday 60 minutes @ aerobic
Friday 10 miles @ long pace
Saturday Cross-Train
Sunday 40 minutes @ aerobic
I have ordered one of the Lydiard books, so for a week or two will be jiggling around.
I have the understanding now, that what I need to find a way of measuring (even for my own satisfaction that this system works) my pace at various HR levels and the consistency of my pace on various workouts. I have yet to decide on how to do this. My changing patterns of work within a week, which affects my choice of route, do not make this so obvious, just yet. Suddenly, Dublin/Kildare seem hillier than Kerry! I also want to study the evaluation procedures suggested in Lydiard books etc.
Today, for example, the mile pace ranges from 5:52 to 6:18 (the penultimate), the last was 6:10. There are some changes in elevation on the route, however, which are certainly an influencing factor on pace.
I have questions. Should I ever do speed work while building base? The Pfitzinger/Douglas book is inclined to say 'no' (p. 20).
Monday: Distance 6.47km/4 miles; Average HR 141bpm; Average Pace 5:57 km/h. (I should add this was an unusual work out, seeking MHR).
Tuesday (long pace/zone 2): Time 60 minutes 4 seconds. Distance 9.71km/6 miles; Average HR 142 bpm; Average Pace 6.11km/h. or 9.57miles per hour.

A few thoughts: I should settle on kilmoteres or miles, maybe?
As the time goes on and I decide on various workouts, I might use an excel sheet to tabulate changes in pattern.

Articulating aims:
(1)  To run MP at same time as half marathon pace or, at least, closer to it.
My current MP is 6:12 km/h or 10mi/h
My current H-MP is 5:25km/h 8:37mi/h.
(2) To improve my pace for the Marathon. I want to do it in 4 hours. That would be a steady pace (no fading) of  09:10/miles; 05/41km/h.
(3) To run faster, longer in MP through improving aerobic fitness which will be accomplished by longer, slower runs in the coming weeks with more specific speed/endurance workouts later in the year.

Final note for the day, I have also learned how to change the face settings on the Garmin. I can now see my HR in one of the windows. It's not just a little changing tiny number in the corner of the screen. The Garmin is just amazing!