Mr T,
I'd had a similar idea to you regarding the stickers, but decided to use Campagolo ones as they are an Italian brand.
http://www.ebay.co.uk/itm/CAMPAGNOLO...item5d254f7a92
The extra holes look great but I fear if I tried they could be all over the place.
I love the style of your seats but having driven down from Norwich to Dorchester in total comfort, I'll be getting a quote to have the original seats retrimmed in something more appropriate than the horrible beige plucked ostrich finish.
Cheers, Bob.