Hi people, I need an advice about increasing the height of a font. I have some overlapping issues going on when I added complex diacritics to a font. I saw some people change the shapes of glyphs to make them smaller but this is not an option now, so I was thinking on changing the ascender value to have more room. Is that something common to do in this cases? Thanks.
Check the resource below regarding vertical metrics (ascenders, descenders, etc.)
Adding two special parameters - winAscent, winDescent usually solves the issue you are experiencing. Apart from that be aware of typoLineGap and experiment what works best.
Was digging into that without any result. I added to the Regular Master, typoLineGap, hheaLineGap, and vheaVertLineGap with a value of 1000, just to test it out but nothing changes when export. To ensure that I am not dealing with cache issues, I changed the underline position, and worked. Is there something I am missing?
What do you want to achieve?
Basically, increase the space between lines 
I supposed it is the *lineGap parameters, or I need to increase Ascender value?
Increasing the LineGap depend of the applications or web browser that is rendering the font. Remember that you have two tables, the hheaLineGap and the typoLineGap. And some applications will trigger a default 120% of the embox if the hheaLineGap is zero.
Besides Glyphs Vertical Metrics Tutorial I recommend to read other public papers about this:
Where? In which apps will the font primarily be used? Like @Realist, I also recommend reading the Vertical Metrics tutorial.
Keep in mind that you only place a recommendation in these values. An app displaying the font may only be using it for the first line offset.