Question: 2019 Ernie Ball MM Valentine (INTONATION and SETUP) Questions

I have questions about my new Valentine hard tail and I’m hoping I can get some answers in which I haven’t found on here searching in the forum so far.

I want to change the strings from the standard 11’s he uses to 9’s. I’m looking at the hard tail which is covered by a chrome plate. I see horizontally, that there’s alan key (ends) screws through the holes of the cover plate. So..

-doesn’t look like you need to but should the cover plate come off before adjusting that? It would probably make it a bit easier from the looks but wondering.

-what size alan key is used? I tried a 2 but I don’t think it fit.

I think that’s all I’m looking for at this time.

Thanks in advance.