I know my Garmin 500 is 2-3x faster and picking up signals and than my Timex was.
I'm just doing the same as I've done in all my races, put my garmin on in T2. My foot pod will get a descent estimate of pace and distance at first anyway. Just make sure you train it on the satellites on Saturday and again Sunday morning. I'm going to access my T2 bag and put it in on Sunday morning and only check my race belt, shoes and visor in my T2 bag on Saturday. I've had the unit not going into a full standby mode and drain the battery overnight before.
But again, a foot pod is a good work around for the first mile or so. It also gives you cadence, so you know, objectively, when you run form is falling apart.... not that there's much you can probably do about it.
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