created site ini for clipmyhorse.tv

u can set the maxdays to whatever you wish but here alot more data.
the max setting is maxdays=31
since all the data is on a singe page it should also be a x.1
from the manual
maxdays, specifies the number of days n for which TV guide data is provided by the site, followed by how many index
pages p is used for it. If n and p are equal, e.g. 7 days on 7 pages, you can either specify 7.7 or just 7. However, if the
site has a multiday e.g. a weekly index_page 7.1 must be specified.

also there is uni encoded characters in the data.i think u meant to do this instead of json decode?
\u0027 is uni encoded '(Apostrophe).
example
"secondLine":"Pan American Cup, presented by Rolex - 1.55m\u00271.60m"
json encoded data would be a escaped
"secondLine":"Pan American Cup, presented by \"Rolex\" - 1.55m\u00271.60m"
so u need
index_showsplit.modify {cleanup(style=unidecode)}
i usually do it before jsondecode

personaly if i see json or uni encoded data i put both(it wont hurt anything).

only other thing is your titlematchfactor
generally i use 90 unless there a specific reason not to.
from the manual
titlematchfactor, e.g. titlematchfactor=50 , this is a number from 0 to 100 that specifies how strict the title comparison
is done by WebGrab+Plus (as discussed in 2.1 The show update process). Some sites use different show titles for the
index pages and show detail page. Start with a high value e.g. 90 and adjust to lower if too many unnecessary show
updates occur. (see also 4.5.1, element index_title). A value of 0 disables title comparison.

its a important setting for how webgrab performs updates so u may want to read the sub sections mentioned above.

for a first ini u did good.
congrats.

Suggest using regex to use ([^"]*) with this will stop at first " Try not to use it in title scrubs, many times title contains inside the element " example you scrub title: {"the horse is a "devil" at night"} in this case the result would be "the horse is a" as the first " is right before devil. So avoid it for title.
Also set * @MinSWversion: V5.0 many elements and calculations have changed with newer versions and you will get wrong results setting version 2.x or 3.x

I did few fix also as Blackbear already mentioned
1. The site is 30 days in one page, i checked it goes up to 20 april, so you set maxdays=31.1 (xx days in one page)
2. I think timezone is UTC (did you set +1 as per local time?)in such case you should set Europe/Berlin
3. A better way to do showsplit, you get what is between {"data":[xxxxxx]} with separator BS,ES,etc etc and with regex you "replace" },{ into | thus dividing split
4. if you have done cleanup unidecode and jsondecode in showsplit, you do not need to repeat it in single elements (in index)
5. see showsplit debug, make life easier
Anyway not bad !!