Another pacing question

In training for my first marahon, I took a bit of a guess at what time to aim for. I use my half marathon time, but it was from a while ago and not during much training, and so aimed for a sub 4.15 (thinking sub 4 was within reach but perhaps needed the experience of my first marathon, so would aim for sub 4 next time round).

I'm slightly questioning this pace now. My LSR's have been slow...I've purposefully not looked at my watch and run comfortably at a pace I can have a conversation at. I feel I'm going very slow (in fact I usually think it's too slow), but they all end up with an average moving time of 9.45-9.50. So what sort of pace should I aim for for the actual marathon? Aim for 9.30 but if I have some in the tank, go harder at the end? I've done 18 miles at 9.45 and it felt comfortable and I could have carried on. My mileage isn't that high (mid 30's atm), so maybe still aim for 9.30? Just feel perhaps I should aim for more?

To add to this, I'm planning on doing the Hyde Park 20 miler. Would it be a good idea to maybe try out 9.30 pace at this (it's 6 weeks before my marathon) and see how I get on? Thanks!

You ideally need a better setup before thining about dropping 15-20 second per mile over marathon distance of such a low weekly mileage. More than likly 9.45 is going to be your race pace. The Hyde Park will be a good indicator however may be a very bad idea for someone who is operating of such low mileage, in terms of timescaling i mean. I think it may be more beneficial to do a 'test' over a shorter...maybe 10k and use a calc(mcmillan) to give you an idea on where your fitness is.

Thanks for this. I have been unable to get out muchfor various reasons the past few weeks hence the low mileage, although have been cross training. However these coming two weeks I have a lot more time and so would like to push the mileage up a bit more. Is increasing by more than 15% very unwise?? I will obviously listen to my body as to what is best...but I'd like to get the mileage up but don't know how much is too much....?
(Also, did a test 10k -not a real race but I did a test run as part of my training a few weeks ago, that put me on target for a marathon pace of 9.10. I am a bit wary of these calculators so feel it might be off a bit...)

Also...another ps....the current mileage is based off 3-4 runs a week. I am able (for the next couple of weeks at least) to fit in another run, or even two...would another run of say 5-6 miles be an ok way to push the mileage up a bit, or is that too much?

Was thinking over the next two weeks to increase the mileage up to 40, drop back a bit for a week or so, then hover around 40, with a max of 45.