try a charge spoon. lots of people get on with them, and wiggle will have one with you sharpish for £22.49
tilt the nose up a little further than you think to stop you sliding forward and see how you get on.
they do get more comfy over time, but you'll get a good idea soon, and if not you'll shift it on here for £15 easily, so no great loss.
otherwise try a SDG bel air – another MTB rather than roadie saddle, but another popular shape, with a fair amount more padding than the spoon.
hth
(i'll be riding LEJOG in september on a charge saddle – a knife if it breaks in ok if not my old spoon – have fun)
oh, BTW, +1 on spending more on shorts. well worth it. minty arse lard/sudocreme etc too.