Building/designing 40k ruins help.

Not a tournament player, just casual stuff with friends but we try to follow WTC style rules and layouts for terrain because the table has such a dramatic effect on terrain and it gives it a semblance of objectivity and fairness. Basically I'm about to make a fresh batch of ruins for my table and wanted to know what the best design/guidlines were to follow to make the most playable/fair/fun terrain.

In my mind this boils down to 3 main queries:

1) Do I make ground floors physically opaque or with windows/doors?

2) How tall are floors on buildings? 3", 4", 5"?

3) Do I make sections with shorter walls (2" or less)?

I feel like my playgroup have never perfectly understood the intricacies of ruins rules, and we've flip-flopped between playing with first floors opaque and open, which has such a dramatic difference on how the game plays for melee vs ranged units. I've seen discussion around on how people are coming round to playing with first floor windows open, and I was wondering if maybe the perfect balance is to build the ruins 50/50 physically open and closed ruins, some walls definitely opaque and others with big windows so it can be played true LOS. Another factor is that I play a lot of big bugs nids, and whilst I don't want to advantage myself, having ruins with base sizes and wall designs that don't cause my units to just go nowhere or tangle their overhanging claws in everything would be good. Basically looking for some advice or templates that people would consider balanced and easy to use, and stop me from having to have a 10 minutes discussion pre-game with my friends about how ruins work for today.

Bonus question: When playing with artificially opaque ground floors, do tall things that stand in those ground floors and poke up to second storey windows (e.g. deathleaper claws, tyrannofex vents) count as out of line of sight?