I was thinking GIII with hushed Speys would be a solid compromise. I couldn't poke many holes in Hubbards logic. Read it for yourself here
Hubbard Aviation Technologies QS3 Hushkit . That combined with this
Maintenance Costs Dropping for Spey-powered Gulfstreams | Aviation International News seemed to reinforce the idea. As for ideas that involve "saving money" by buying a more expensive aircraft because one can plan(hope) for a higher residual many years in the future, that is a bet for another player. I learned many years ago that the only sure way to limit downside risk is limit the money put on the table at the beginning. Works in Vegas. Works in business.
That being said a G-IV option is intriguing, say if Wendy's could be convinced to take their medicine on
1994 GULFSTREAM IVSP Jet Aircraft For Sale At Controller.com the FAA registry and their financials indicate they have already gone to using Netjets to meet their aviation needs. My perfunctory research says $600-800K total for the ten years on the engines.