Very cool Harry, have you been apprenticed to Mr Waller?
Can't see any problem with the electrics to the weapons (in my professional opinion

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For tech checks, probably best to check all combinations for size & weight as it's hard to judge which might be the worst combination when not assembled. Similarly heaviest is not necessarily biggest. To save a big delay in checking, just interleave the checks of each version with everyone else's robots.
The rules actually say you have to be ready within 5 MINUTES of a fight being called.

If you can be ready within 60 seconds it should be OK. A bigger problem might be figuring out who you will be fighting next to allow you to choose the correct weapon. A better way of letting people know about fights in advance would be nice...