In the last months, Monique and I spent time on collecting and analysing data on the topiary trails.
And we got a lot of help from fairies sharing trail info with us. Many thanks for that!
Though we haven't cracked the algorithm completely, we are happy to announce that we found a big part of it, so that we could turn our data into a calculator.

So please check out the calculator page:  http://myarduinoprojects.com/flcalculator/

To give you an idea on the chance of a match, for every level a percentage is shown. We will refresh regularly whenever new data is shared. (Level 1/Red is excluded, no surprises there.)

This is how it works:
Select the level and first critter on your trail from the drop down menus and fill in your garden id and pot id.
You can find your garden id from your garden wall url, this is the link that ends with .../fairygarden.php?id=xxxxxxx in the address bar of your browser.
You can find the pot id in several ways, but most easy via the itemid as visible in the Use-link of the storage area/greenhouse: Hover over the Use-link and at the bottom of your browser it will show the URL like .../storage.php?action=move&itemid=xxxxxxxx
Or click on the use link to put the pot in your garden, the address bar of your browser will show the URL similarly.

For anyone that has completed a trail, please check whether your pot yields a match, if not please share your garden id, pot id and the order of the critters for that pot on my backwall so we complete the database.

Thank you all for your feedback. With the few replies on my backwall we already improved the percentage with the following:
Orange: 40.6% to 42.2%
Yellow: 37.6% to 38.2%
Green: 34.3% to 34.8%
Blue: 29.1% to 29.4%
Indigo: 22.5% to 22.6%
Violet: 14.2% no pots = no change

Awesome job! Took me some time to discover with the pots I know that I'm entering wrong garden ID (I used the same as for alchemy calculator and it's not the same haha :))

I see new entries are flying your way now :) Looking forward to seeing some of the stats improved, especially the violet and indigos.... tried to enter all my remaining 18 violet pots and all were no-match except for one partial. Still it's going to be a huge help for some!

Wow! thank you!!

Thanks. This will be a great help.

We found a little bug in the output in case your garden id times pot id results in a number ending on 200. Will fix this when I am back home this evening (prob 9 hours) as I can't fix it from here.

as soon as i have room in the garden- quest complete- i will check all my pots for you for data- thanks for the good work!

Issue is solved and page is updated with the latest feedback.
Orange: 49.0%
Yellow: 44.1%
Green: 38.5%
Blue: 31.6%
Indigo: 24.4%
Violet: 14.8%

I have completed all colours but I have two violet pots - when the last put goes into storage does it sit on the left? If so I can send you my violet pot order

You can tell them apart by their ID number, Charlotte - if you hover your mouse over the Use link when they are in storage, you should see the ID number pop up in the bottom left hand corner.  Bram lists some other ways to see the number in the first post :)