I have a question for those that have experience racing a 100km...So how long do you spend at the half way feed zone? do you just change bottles, chuck food in your pocket and go withing within a few seconds or stop for a minute or two?
I've only done three 100k races (three MTB races actually), but in terms of pace i suppose i give it some reasonable stick. So here's my 2 cents' worth...
To be talking about podiums, you're obviously riding up where there's some action and can pedal 100km offroad no dramas. So if you find you're dying to hang around at an aid station, you've been on the pace a bit too hard and you'll pay for it later -- if you take a break at that point, you'll get some freshness back but will finish just as far back anyhow.
The optimal pace is an even tempo. Obviously you can never get it totally scientific in MTB, as you're punching climbs one minute and riding out rocky descents the next. But if you train long and hard for it, you pretty much know where your sweet spot of intensity is during the race.
Regarding aid station shenannigans, be there only as long as it takes to get what you need. If you're riding sub-5 hours, you don't need a roast dinner and can take ample fuel in your jersey pocket, viz. bars & gels. Heck, you can fit a day's worth of gruel in a camelbak. But if you'd rather rely on what's on offer at the table, then stop, jam in a face full, and get the hell outta there. And if you need liquid, then fill 'n' go.
If the mule starts to flag and needs some good oil at any stage, same applies: lube her up, then get on it.
Before my last 100k, i spent ages thinking about packing and stop strategies. Three aid stations allowed me to ditch the pack and ride with just 2 bottles on board, and the bottle drop provision meant no fill-up necessary -- just lock & load. Jersey pocket had bars, gels & pump, and my small saddle bag contained 2 individual allen keys, spare tube, 2*CO2 cannisters and a fun-size sample of chainlube (complimentary in the showbag).
Compared to my first two races, i was riding with an average of something like 1-1.5 kg less ballast the whole way, which made so much difference over the long haul. Even if you have to stop quickly 2 or 3 times to fill up with water, the fact that you'll be riding literally minutes quicker than if you start with a 3L bladder stuffed in a pack full of unnecessary crap will mean you'll finish a lot less sore and be several places further up in the lunch order queue at the end.
Oh, and if the race you're planning for is Mogo, get your roadie mate to standby with supplies ready on the oval at 50k. So there's two fresh bottles taken care of, plus the second 50k worth of fuel. Quick refill at 30k (or again, get your mate to locate that table to keep you moving), then a 15 second refill at 80k with a can of bull thrown in the pocket, and you're home.