Mainesail - thanks for the input. Yes, I forgot, that was the shipping weight!
I had considered Garmin, but had a look at the Blue charts for my area (South Shore of Nova Scotia) and there was very little detail. Also heard this from other local sailors, who said the Gramin charts did not cober this area well.
I don't think the sails catching would be a huge factor, on my boat. Last year, I had the mount with no dome (old JRC1000 died), and only casught a sial on it one time (not a smooth rounded edge), and I was tacking a drifter, which I shoudl not have been doing. No issues with either a 130 or 15o Genoa.
That said, the small one is likely all I need. Just wondered if the larger one was worth the extra cost, weight, etc. The 24" dome may look out of place as well. on a 30' boat.