I've started playing a couple of days after pewdiepie's video so under 2 month I think ? (some of my stats go reset at some point ><)
I was playing slowly at first and in an non optimal way, things started to get serious when I began automating the share farming... 2-3 weeks ago I'd say, I was around level 20 iirc.
Let's just say my multiplier level is kinda obscene thanks to the event and I was level 6 before.
So I'll probably max out all my decorations this week except the neon. I couldn't have done that with a long stock market run
I thought about doing that at first tbh, the best is doing diamond > coffee > gold > coffee.
It'd go a lot faster with the coffee too.
iirc coffee = ~20% gain, gold ~50%, diamond ~200%
If you do only gold/diamond: 2*1.5 = 3x your money per hour, with coffee: 2*1.2*1.5*1.2 = 4.32 per hour
So 2h at 3x => 3*3 = 9x your money, at 4.32 => 18.6624, you get the idea ^^
Keep the gems to buy multipliers in the store, you can get gems in the tournament, daily login and the higher level chest (I'm not sure but I'd say you need to open at least 100 chests at once to get gems)
I'd also keep at least some of the time skip for the tournament to reach an higher reward tier.
Check out the wiki for the decoration upgrades : fapceo(dot)fandom(dot)com/wiki/Upgrade_Order