Hey Javi - just for you I ran out to the garage and grabbed both from the parts shelf. Here's a side by side with a standard 3-spoke and a Tequipment 3-spoke (you know I'd have one
).
Without digging around for a micrometer to measure, they both feel the same in my hand. The two thickened leather grips at 10 and 2 on both wheels fit exactly the same way in my hand, as do the carbon fiber grip vs the leather grip. Eyeballing both, I can't see any apparent difference in diameter on either wheel. I think you'd be correct in having them keep the grip the same diameter as your stock 3-spoke.
Who are you having do the work for you?
BTW - I didn't know you had Sport Seats - cool!