What's the risk in running a cylinder with the cross hatching worn down to almost nothing?

I'm doing a top end rebuild ATM and after A good clean up the cylinders are looking good, but the top cylinder in the top 2cm of Nikasil only has the slightest amount of cross hatching -in some areas virtually none.

I know this isn't good, but I'm considering a 275 or 300 conversion at the next rebuild ( opinions on either are welcome too) So I assume I could /will loose some compression but is there anything more sinister likely to happen if I run this cylinder?

Also electrosil quoted $440 for re-Nikasil anyone know anywhere else in Aus that I can get a quote?