200% + Oversizing?

What orientation are those panels? If E/W then you will have very little clipping with a 5.5kW inverter over the whole year. I doubt it will be more than 10%. Edit: ChatGPT says it will be just 1-3% and even with both strings pure south just 10% LOL

I would always put up as many panels as you possibly can. Extra panels are cheap to install and as such have a very quick pay back period

Careful with 14 panels on a string. Most panels are in about 40v each, so 14 of them would be 560v. Looking at the datasheet for that inverter

inverter_datasheet_Sungrow SH5 Hybrid Inverter.pdf

Max input DC side is 600V. So you would be pretty close to that limit .If your panels were more than 40Voc, or it was a cold day, I could see you tripping that limit easy enough. 13 panels is probably a more realistic limit unless you are getting panels with a Voc of <40v

The problem usually manifests itself as I understand it on cold "scattered cloud" days. i.e. The panels are in the shade as the sun is behind the clouds, and cool as a result, and then wham….the sun comes out from behind the cloud and there's the issue.

On a cold completely blue skies day, it may not be an issue as the panels will be gradually wamed by the sun as the day progresses, so you may never see the issue.

As unkel says, while you may put in a string technically below but close to the limit and be fine for years - really the data specsheet is there for a reason and you don't want to be pushing right up to those limits. Personally I wouldn't be going within 10% of the max, but that's me - others will have different opinions and good luck to them.

As for what happens if an over voltage occurs, I've only anecedotal information from watching youtube videos over the years. Some makes/models will simply shut down production and then retry in 15-20 mins (meaning you've lost that generation time at least) and it will iterate until the voltage is within specs. Others could be damaged by blown components etc just not really a ROI on doing it.

Sounds like your numbers are good though.