I totally get the struggle... that Noctilux is a beast and Charleston humidity is no joke. I used to be a purist too but your hands eventually give out. Since you are using an M11, you definitely want something that fits the specific geometry of that top plate perfectly so it does not move. Here is a breakdown of what works for heavy glass based on my experience:

• Match Technical Thumbs Up EP-MX for Leica M11
• This is the best choice if you want something solid. It is made of brass, so it has some weight to help balance the lens. The fit is very tight and it will not budge when you are moving around. It is expensive but it basically lasts forever.
• Leica Thumb Support M11 Black 24028
• The official Leica version is decent if you want a perfect finish match. It is made of aluminum so it is lighter, which might be a pro or con depending on how you like the balance. It looks very integrated with the camera lines but costs about the same as the brass ones.
• Haoge THB-M11B Metal Thumb Rest for Leica M11
• This is the practical choice. It costs way less but still provides the grip you need. It uses a silicone insert to keep it from scratching the body, which is a nice touch for the price. It is a solid middle ground if you do not want to drop 200 bucks. If you are doing long wedding days, the Match Technical is probably worth the extra money for the stability alone. It handles the torque from a heavy lens much better than those cheap ones. Just make sure to get the specific M11 version tho because the older ones will not sit right on the new body. Let me know if you need more help deciding!

Are you using a half case? Over the years I found the Lensmate Thumb Grip for Leica M11 Black is way more secure for heavy glass... the rubber bumper really helps with the slipping.

I love the Haoge THB-M11B Thumb Rest for Leica M11! It is seriously amazing and way cheaper than official gear tho.

• Solid aluminum build
• Matches finish perfectly
• Saves you tons of cash!

Regarding what #3 said about "Are you using a half case? Over the years I found the Lensmate..." - honestly, I'm gonna go against the grain here and say be really careful with any thumb grip when you're rocking that Noctilux. The accessory shoe on the M11 is solid, but it really isnt meant to act as a primary leverage point for a lens that heavy. When you're out in the humidity and your hand is straining, you end up putting a ton of torque on the top plate. I've seen shoes get wobbly over time, which is a nasty repair bill you dont want. tbh you're probably better off looking at a dedicated hand grip that attaches to the baseplate. It shifts the weight to the tripod mount which is designed for that kind of stress. It might not be as pretty, but it's way more reliable for a long wedding day than putting all that pressure on the hot shoe.