In general it's safe to say when pokersites are vague or at least not straightforward regarding the net rakeback to be earned, (earning chests, spinning wheels) players are disadvantaged. Thanks for sharing the spin results @xPOPOVICIx, this is the only way to find out.
Another shady way of calculating how much one raked is the Player Value Index (PVI) Method.
This is from their rules section at:
https://www.ggpoker.com/network-rules/
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1.5. Player Value Index Method Rule
Each Player at each Participating Operator is given a value between 0 and 2. This value is called the Player Value Index (“PVI”). The PVI for each player is made up from the scores on each games, with an individual weighting.
1.5.1. Hold’em and Omaha scores are determined by CHB Index, Swing Index, Potsize Index, etc.
1.5.2. All-in or Fold score is determined by All-In Index, Jackpot Index, Winloss Index, etc.
1.5.3. Tournament score is determined by Overlay Index, Satellite Index, Buyin Index, and Skill Index.
1.5.4. All scores are subject to change.
The combination of the scores gives the PVI for each Player at each poker room in each Group.
This PVI is then used to allocate Rake between Participating Operators. The Rake for each Hand is allocated to the Participating Operator per that Participating Operator’s Player, in the ratio of that Player’s PVI times Rake for the session.
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This indexing of players' rake contribution can't be looked into, and therefore it's another factor they aren't transparent about and is disadvantageous for players too. In case the level of competition isn't worth it, consider to play at the GG Network twice in my opinion.