advice ranked Heimer

I am looking for some advice. I am silver 4 and have shifted into maining Heimerdinger in ranked. All in all I like playing the champion. I am looking for tips in regards to getting better at him and ranking up. I tend to prioritize objectives over kills, but I know I need to get better at warding and grouping with the team.

Is it ever worth it to dodge a game in champ select if your team has a bad comp? I started out playing Heimer by rushing Morello and now I rush zhonyas. Should I be rushing first item situationally or stick to zhonyas? How should I be analyzing the fights in terms of what form of my ultimate I should be using?

Some matchups I have found impossible or very difficult are Gnar, and skilled riven/yasuo players. Are there ways to beat these champs? And or should I avoid facing them as much as I can?

What are some of the best ways to encourage and lead your team when your team is behind or just barely breaking even? Seems like even when I try to encourage tilting teams it rarely helps.

Sometimes I will duo and go top or mid while the other half of the duo goes adc or support. Does it matter a lot which roles are chosen by the duo?

I have been running teleport and flash as my summoners on heimer. I have found the advantage of being able to jump from top lane to drag or bot or back to lane useful. Should I be using other summoners?