119 Dungeoneering would be too hard without a permanent team since the chance of a delve challenge would still be like 1/22 or something. That's definitely out.
It's either all 98s or fully max. Although... If I was to stay all at 98, I could still do all 99s in a day but I could get untrim Inventor which a lot of skillers wouldn't be able to do any way (since they'd have 99s), where as I can just save my cash for it now.
I think that will be the best idea.