TG in FCO departs from a different terminal than LH - it is the Non Schengen area. I suppose the Lounge you will be using is Le Anfore - which is even worst than that, it is completely underground no windows and no natural light. Food and beverages offerings are less the basic , there is usually a barman who will pour your drinks on request and some 'tramezzini or mini pizza ' that is all!
I usually drop my coat and extra bag there and after I have a drink I go upstairs to the 'light'. Again TG doesn't have any better choice . Whoever designed those lounges bought it would have been a 'jail type' of room!!!