Just saw this while looking for bag inserts actually. I went through the same struggle last year before a trip to the PNW. I tried to go super cheap at first and that was a total disaster lol... the wind just knocked my setup over almost immediately. I ended up getting the Sirui ST-124 Waterproof Carbon Fiber Tripod with ST-10 Ball Head and honestly its been a tank. Its way under your $650 limit which is nice because you can grab extra batteries or filters with the leftover cash. The best part for Iceland is the waterproof seals on the legs. I was shooting near the ocean and didnt have to worry about sand or salt water getting into the twist locks and ruining them... which happens way more than youd think. Cleaning out grit is a nightmare. One thing about the PD... i used my friends and its super compact but those really thin leg sections at the bottom flex a bit much for my liking when its windy. If you do go that route definitely dont extend the center column at all. I found that just keeping the tripod lower to the ground helps a lot more than hanging a bag sometimes. If the bag starts swinging in the wind it actually makes the vibrations worse on a high res sensor like the A7RV. If you want something even sturdier but still light check out the Slik PRO CF-634 Carbon Fiber Tripod paired with a decent head like the Sirui K-20X 38mm Ball Head. Its a bit more old school looking but it gets the job done without the Gitzo price tag. Just make sure you practice the leg locks with your gloves on before you leave!

Quick follow up while I'm thinking about it... are you mostly shooting wide landscapes or are you bringing heavy telephoto glass for those Icelandic vistas? That 61MP sensor shows every tiny vibration so the lens choice matters a lot for stability. I have been extremely satisfied with the Leofoto LS-284C Ranger Series Carbon Fiber Tripod for similar high-res work. It is basically a clone of the higher-end brands but for about half the price, which fits your $650 budget easily even with a high-end head. Since it lacks a center column, you get way more rigidity in the wind than the Peak Design would ever give you. Honestly, I dont think you need to drop Gitzo money to get professional results. I paired mine with the Leofoto LH-30 Low Profile Ball Head and it has been rock solid for me. It might be the middle ground you are looking for.

Honestly, dont bother with Gitzo and get the Benro Tortoise 34C Carbon Fiber Tripod! Its freaking amazing in the wind and way cheaper, plus no center column means zero wobble!

Coming back to this after seeing the budget mention... honestly, I was in your exact shoes before a trip to the Lofoten Islands. I looked at the PD too but the vibration damping just didnt feel right for long exposures. My choice ended up being the Sirui ST-224 Carbon Fiber Tripod paired with a Sirui ST-10X Ball Head and honestly, no complaints at all. It handles my A7R setup without any of that micro-jitter you get on thinner legs. The reason it works well is that triangular center column design. It makes the whole thing collapse really slim like the PD, but it feels way more like a real tripod. Using those twist locks is easy even with thick gloves on, which is basically a requirement for those cold winds. Tbh, the market has shifted so much lately that you dont need to drop $1k on a Gitzo to get that level of stability anymore. I am very satisfied with how it balances weight and rigidity for those high-res files.

Unfortunately Ive had nothing but issues with these thin travel legs lately. Its really disappointing how much they flex under a real camera. For Iceland, you really need something that wont fail in a gale.

• Try the Feisol Tournament CT-3442 Rapid Carbon Fiber Tripod. Its extremely stable for the weight and lacks a center column to wobble.
• The Slik PRO CF-734 Carbon Fiber Tripod is also great. Its beefier and wont vibrate like the PD does.