Oh boy, it's started
Lagging idle after revving (which, incidentally, the TS doesn't really like anyway) is probably an airleak around the carb intake or airbox. You say it's a custom air flter job - got any details/photos? There are at least 4 perishable components to the TS intake system - paper air filter, filter housing sealing band, airbox-to-carb snorkel and airbox sealing plug....and that's not counting even counting the the carb gasket or cold-start plunger. The snorkel is also particularly prone to cracking/leaking.
Buy a spray-can of carb cleaner (don't use WD40!) and with the engine ticking over, spray a little around the intake manifold, intake snorkel, cylinder head, exhaust sealing nut, etc. If the idle drops, or the engine dies, it's got an airleak. If not, it could just be running lean because of the new exhaust. Needle clip should be 3rd from the bottom - maybe 4th since you say you're running a 'sport exhaust', which will also be doing nothing except lowering your MPG.
Float height is 27mm when 'closed' and 34mm when 'open' - see attached.
That should keep you busy for a day or two...
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