Unfortunately manufacturers do not include the weight of the battery or full propane tanks when listing "dry" tongue weights... The Surveyor 247bhds is 5800 empty, w/empty tongue of 580 so your tongue weight will be over your TV's TW limit of 600 as soon as you calculate the weight of your 12V battery & 2 full propane tanks - let-alone any gear you pack in the pass-through storage, under the master bed, or in the master bed closets...
For instance, our TT is 6400 empty, w/empty tongue of 640. However, ready-to-camp we're at 8000+ w/tongue weight of 1100... The tongue weight goes-up quickly because, like your TT, most of our storage is up-front & the dry weight doesn't even include the weight of the battery or 2 propane tanks. Our pass-through storage holds necessary camping gear like lightweight leveling blocks, 30A extension cord, and freshwater hoses. Under our (front) master bed we store all of our comfy camping chairs, and our (front) master closets hold the clothes we need for 7-10 days w/out washing... We also swapped-out the lightweight/thin mattress for a heavier comfy one... This all adds up.
IMO the Surveyor 247bhds @ 5800 empty is still 1/2 ton pickup towable & it might be OK for short trips behind a longer wheelbase SUV like the 1/2 ton Armada, Yukon XL, or Suburban. However, your Mercedes GL 450 should only be paired with shorter hybrid trailers. Crosswinds hitting a 30' TT will push you around too much even if you could keep the tongue weight within specs...
2011 RAM 2500 ST Crew Cab 5.7 Hemi
2011 Primetime 3150BHD Touring Edition
Days camped in 2016-36
Days camped in 2015-37
; Days camped in 2014-31