My soft-top has the 40mm latches, but the leading edge of an old Custom Tops hard-top I'm about to restore has latch mounting holes for the 30mm latch - are both size latches compatible with my 40mm latch hook?

I would measure the distance between the latches on both the soft and the hardtop. One time I transferred a top frame from one Spider to another and the latches would not line up. There is adjustment in the conv top latches if you loosen the screws, not sure about the hardtop latches.