Avoid 1-hose portable units at all costs.
Those units are weirdly popular and trendy... and this is a mistake because of their horrible efficiency.
This is not bigotry. This is science.
Even if you are painted into a corner and are forced to use a "portable" unit, hold out for a 2-hose unit (which sends 2 hoses outside). Unfortunately they are not popular (most buyers are bad at physics), and you'll pay a premium - but you'll earn it back several times over in better efficiency.
Some 1-hose units can be "hacked" with duct tape and some dryer hose to become 2-hose units. However many cannot, because they use 1 common intake port for both process air and room air. I've seen people adapt those, but they had a home shop.
If this is still unclear, watch this video.
Go window unit if at all possible.
Window units are also cheaper.
Yes, I know 1-hose portables are "popular and trendy", but if everyone else jumped off a cliff, would you?
The units are just terrible. They are inefficient, they require something be done with water, and worse, they suck humidity into the rest of your house making humidity even worse there, and causing mold.
Sell the thing to someone "trendy" and get an old fashioned window unit. If your window is narrow, shop for the smallest window units - they are surprisingly narrow and I've done 2 narrow windows successfully that way, including a casement window. (which required cutting and fitting some plywood and trim to fill the open space... On the casement we were able to stack two 5000 BTU units vertically, even. Or, you can get actual "casement" units that are taller than wide.
The window units get rid of water by simply dumping it on the "outside" side.
Why 1-hose portables are bad
Now they do make 2-hose units that are more efficient and do not suck heat and humidity into the rest of your house. However that does nothing about the water problem.
The 1-hose models suck in humidity into the rest of your house, because they are pushing air out of the room through that 1 hose. Where does replacement air come from? Every leak in your house. Most of which are in other rooms that aren't being air conditioned. So the humidity just comes pouring in.
In any case, they are ejecting conditioned (cooled, dried) air from your space, and drawing in unconditioned (hot, wet) air. Thus they are wasting conditioned air and making more work for themselves. This hurts efficiency badly, and US ratings of the machines have been revised downward to reflect this. You often see 2 numbers; the older number is what the unit would do if it were a 2-hose unit. You're paying the electricity for the difference.
By adding an aux tank, you broke the auto-shutoff
Our portable AC unit drains into a 3 gallon jug. When the jug is full, we empty it. This summer, the humidex has been bananas and the jug may be filling in 2-3 hours. The fill rate is less predictable than I expected.
The unit already had an internal tray, and an auto-shutoff when that filled. But like me, after emptying it 3 times in 6 hours, you said "this is for the birds". Unfortunately your method, with the jug, broke the auto-shutoff. So now you have an overflow problem.
I suppose you could go with a vastly larger bucket (42 gallon barrel, set the unit on top, spigot on the side to fill buckets to haul the water away? High enough on the barrel you can get a bucket under it.)
I don't see a good way to fix that.
Knowing what I do about hydraulics, I don't see a way to fix that. Affordable condensate pumps are not reliable enough, and wiring a high water shutoff would be absolutely insane given the risk of mixing water + electricity. How would you even attach it to a jug you take away to empty?
The best you could do is put a condensate pump inside the factory, built-in tray... so it never fills up, would be the idea. If the pump failed, the tray would fill and the shutoff would work normally.
But honestly -- this is complex stuff that is going to require actual engineering. Mistakes will be made and all of it will cost you money. Whereas, sticking a window unit in a casement window and coming up with some plywood and trim to seal it - well, it's annoying work, but it's straightforward work. So that is the way I would bet.
I have to say, having done that, life is easy street. I do zero maintenance on it, it just works.