Lets analyze Rshares formula

Top priority : Rating

Use silver league as example

Compare Silver III rating with Silver I rating

Rshares =( rating³/1,000 ) * ECR * bonuses * (1-% of starter cards)

(From splinterlands official note : the reward shares values shown in the game UI for both quest and season rewards will be divided by 1000 to keep the numbers smaller and more easily readable. So we divide by 1,000,000 as below)

For
Silver III : max tier rating = 1299
rating³ = 2,191,933,899
Rshares =( rating³/1,000,000 ) * ECR * bonuses * (1-% of starter cards)
= 2,191

For
Silver I : max tier rating = 1899
rating³ = 6,848,175,699
Rshares =( rating³/1,000,000 ) * ECR * bonuses * (1-% of starter cards)
= 6,848

With ECR=100%, bunuses=0%, non use of starter card

So if we stay in Silver III, Rshares we gained was around 2,191
but
if we stay in Silver I , we gained was 6,848

Rshares gained in Silver I was 3 times of Silver III !!!

From table above,

For Bronze League :
at Bronze III you need to win 85 battles to gain 10 Bronze chests.
at Bronze I you only need to win 6 battles to gain 10 Bronze chests.

For Gold League :
at Gold III you need to win 27 battles to gain 10 Gold chests.
at Gold I you only need to win 13 battles to gain 10 Gold chests.

Second Priority : ECR

Use silver league as example

Compare ECR 75% with ECR 25%

Silver I League
with rating=1899, bunuses=0%, non use of starter card

Rshares =( rating³/1,000 ) * ECR * bonuses * (1-% of starter cards)
rating³ = 6,848,175,699

At ECR 75%
Rshares =( 6,848,175,699/1,000,000 ) * 0.75 * bonuses * (1-% of starter cards)
= 5136.13

At ECR 25%
Rshares =( 6,848,175,699/1,000,000 ) * 0.25 * bonuses * (1-% of starter cards)
= 1712.04

If you compare RShares ECR 75% with ECR 25% there's 3 times different RShares value from 5136.13 drop to 1712.04 !!

At ECR 25%, lets say if you have bonuses 60% (Win Streak: 10%
Gold Foils: 50%)
Rshares =( 6,848,175,699/1,000,000 ) * 0.25 * 1.60 * (1-% of starter cards)
= 2739.27

The RShares value still much less than Rshares value at ECR 75% which is 5136.13 without any bonuses!!!

Summary

1. Always climb to the top tier in the League you played to maximize
   daily chest gained.
   If you played at Silver League, stayed at Silver I
   If you played at Gold League, stayed at Gold I

2. Always keep your ECR above 70% to optimize your daily chest gained.

Hope this article help. Thanks for reading.
Happy Gaming !

Have Fun with Splinterland !!