Use and connotation of 'gelle'

Question

I have long been aware of the use of 'gell' as an informal alternative to 'nicht wahr'. But recently I have seen an increasing use of 'gelle', for example in the comments section of a current ZON article about Die Grünen:

Eine hübsche Sammlung der zusammengelogenen Vorurteile über Karikaturgrüne haben Sie da geschreibselt. Wär ja auch zu schwer, sich inhaltlich auseinanderzusetzen, gelle?

https://www.zeit.de/politik/2019-06/wahlumfrage-die-gruenen-waehler-bevoelkerung?page=20#comments

1. Is my perception of its increasing frequency justified?
2. Is it common in other parts of Germany than Hessen (as indicated in the answer to this question: What is the English translation for the Hessische Wort "Ger"? (correction "gell"))?
3. Does it have a different connotation than gell (for example, that its use is typically regarded as provocative or aggressive)?

Answer 1

1) Is my perception of its increasing frequency (gelle) justified?

No. Gelle isn't used as much as 30 years ago and is replaced by gell or ge. In this picture you can see where gelle is frequently used.

As the source explains

... nur noch für einzelne Orte an Lahn und Main sowie in Nordhessen und im Saarland ist gelle charakteristisch, das vor 30 Jahren als typische Ausspracheform für diesen Satz in einem breiten Streifen Mitteldeutschlands zwischen dem Saarland und dem Süden Thüringens genannt wurde.

gelle is in decline and replaced by its variants where it was once standard.

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2) Is it common in other parts of Germany than Hessen

As stated in the picture's source gelle is mainly used in Northern Hesse, Southern Thuringia and the Saarland. But gell and ge, are known and said as well in middle and southern Germany, Austria and Switzerland

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3) Does it have a different connotation than gell (for example, that its use is typically regarded as provocative or aggressive)?

No, it's the same. (From my point of view)