@Stefano - Any experience with both Fenix PD35 V3 vs TK20R V2? The TK20R looks a little big for carry?
No I have no experience with Fenix PD35 V3.0 but only with V2.0 and earlier versions.
The PD35 V3.0 is not bad as a flashlight but comes with a "small" 2600 mA battery.
It has a cigar shape and a diameter of 25mm, it can be very convenient in a trouser pocket.
The TK20 V2.0 has a 34mm diameter head, it will require a holster or jacket pocket to carry.
Other considerations: The 34mm head offers better light performance and better heat management, the TK20 V 2.0 has 3000 lumens but can hold them for a minute or so It can hold 1000 lumens for 10 minutes before dimming a bit.
The Fenix PD35 V3.0 drops in brightness from 1700 to 1000 lumens in 2 minutes and 40 seconds.
I found this information in online reviews but it is not specified at what temperature the test was done and whether a fan was used or not.
Outdoors in wind and cold temperatures you may be able to maintain high performance for a significantly longer time.
They also have different batteries: 18650 battery with 2600 mA capacity vs 21700 battery with 5000 mA capacity.
To recharge the PD35 v3.0 you will need to take out the battery and connect it with a cable.
In the TK20R v2.0 the charging port is external.
Another consideration: the price of the TK20R V 2.0 is high while that of the PD35 v3.0 is lower.
Personally I would not go into a dense forest with either of them but if you are on an open path or in a deep field the matter is different.
Always consider that the PD36R could be inserted as a compromise between the two.