Agreed, don't waste your money buying the type. The people that operate G4 & G5 could care less if already have a type, they're hiring people.
Your willingness to resign your seniority is probably your biggest asset.>>
Gotta agree with both these statements. Presenting a type-rating with no time-in-type at the kind of flight department you are looking for won't get you hired. In fact, running out to buy one might even work against you, since those who manage well-run operations rightfully take pride in seperating themselves from the kind of operation that asks prospective employees to do so. Without knowing your obvious sincerity at simply trying to make yourself more saleable, it might be thought that you believe THEY are that kind of operation.
From your experience, whether or not you can actually get through training isn't even a question, and you're really not saving them money in the long run since they are on full-service contracts anyway.
501261 was right on...they hire people. A willingness to resign and give up your seniority number is a great asset because it shows you are thinking long-term commitment and don't consider them just a "port in the storm", but rather a quality place where you want to enjoy a career.
The $$ you earmarked for a type-rating would be much-better spent on face-to-face research on where you'd like to work, if an opportunity is worth moving your family for, and setting yourself up as the 1st person in line when a vacancy becomes available. The chances that there is a job opening "right now" is low, but it's always been low with the best operations. People rarely leave them. Research not just the company, but the flight department itself. Spend the money to meet and make contacts, and maintain the contacts with those specific operations that you'd enjoy working for to ensure they know your interest isn't waning. If you do this, it will not go unnoticed by any place you'd want to work for. Eventually it will pay off.
Because of low-turnover and relatively small numbers of employees, sometimes different flight departments take on varying personalities over time. Find one with an atmosphere that suits you, because unlike the airlines where those you work with change every month, working for even a large corporate flight departments is more like a family living in a one-room house.
If it all gels, IMO it's the best work environment possible in aviation. Take into consideration that you might be sitting in a cockpit/rental car/restaruant with essentially the same people for the next decade or more.