The percentage off seems to vary, as does the MSRP and what it's discounted from. Concentrate on the out the door price.
Good deals? HF < 400, JV < 300, Isaia under 800. Great deals? (much rarer) - when HF approaches 300, JV 200. You just have to get used to lots of STP e-mails, know your strike price and keep checking for a deal.
Thanks, I know H-F in 48L fits me but not sure on the JV. I think I tried on an Isaia at Bloomingdale or N-M once, wow so nice. But don't remember which size fit me, I just remember it felt like putting on a well-fitting shirt!
Honestly if only wearing for 4-5 times and year and some of those being for pleasure, I would say go thrifting! It'll take a while but you've got a higher likelihood of finding a WELL fitting suit and staying WAY under budget! Check your local thrift stores or some vintage stores have higher prices but won't have orphans. Good luck!