ohh I like kling's suggestion.
I had a big circle Vans sticker (not as big as yours, it was probably 8 inches) that I placed on my nose, top left and had a few inches hanging off the edge.
Use a pair of sharp scissors/knife and carefully cut away the part of the sticker hanging off the board. I then placed this (I call it the 'curve-slice') at a slight angle, the concave portion adjacent to the other part of the Vans sticker.
I know, kinda hard to explain but it makes your board "match" (w/ stickers at least).
Kinda what Henry said for #1 but reuse the sliced off edge, basically.