I don't know by you already holding a type rating it could prove to a company that you can hack the grade to be issued with a type rating.
But it is a double edged sword. If you get a Jet type rating first most TP operators arn't going to look at you because they know fine that as soon as you get a sniff of a job your going to be away and quite happily pay your bond. And currently there are lots of TP jobs going as TP drivers are moving onto jets.
And the 2 ratings stuff is a bit of a miss leading comment you are only meant to be able to be current on 2 types at a time although there are a few select demi gods out there who fly 3-4 types with various conditions imposed. You can have mutliple types on your license all in date some you can use on the line and others you can't. Normally to swap you need a OPC/LPC on type and a couple of sectors line training and away you go. If your multi-pilot IR on that type has lapsed for more than 5 years i think you are required to repeat the ground school.
Persoanlly I would never even consider a Jet type rating unless there is a job at the end of it. I wouldn't pay for a TP rating either but if you must.