As Vitaliy said: All the heads are by far not usable with more lightweight systems. They are designed for camera systems, which ALWAYS are above 5 or 6kg (or even higher). No matter what accessories you are using. That´s a little bit of a problem with the "bigger" heads.

There are only a few heads which are usable over a very wide range. The already mentioned Sachtler FSB8 is for example one of them (and you can use cheaper 75mm half bowl tripods with it - which is nice). It has a very wide load range (altough with the GH3 alone it will be not possible to balance it out) -> It has a min. load of 1,2kg at 75mm cog (center of gravity). You need to check the counterbalance charts (as Vitaliy also mentioned already):

http://www.sachtler.com/en/products/camera-support/fluid-heads/product_fluid-heads-75-mm_fsb-8__tech-facts.html

So all in all: If you use your GH3 + let´s say your baseplate (and / or monitor attached) it´s possible to level it out. With the GH3 alone it will not be possible. It´s that simple. The bad thing is, that many producers are not offering counterbalance-charts. They just mention the counterbalance at any center of gravity. Mostly 75mm or 100mm. (But also often at 50mm, which is by far not usable because you are nearly always over 50mm of cog.)

Btw.: Also a very good alternative is the Cartoni Focus HD head: (Altough it´s a 100mm head - so you need a bigger tripod. Manfrotto 536 for example is VERY NICE!)

http://www.cartoni.com/web/en/fluid-heads?page=shop.product_details&flypage=flypage.tpl&product_id=225&category_id=1

The huge pros are: Stepless drag control (for pan & tilt), stepless counterbalance control (so it´s possible to fine-tune your counterbalance), a even higher load capacity (& also a higher range) and it´s also price wise not THAT expensive. (The FSB8 is more pricey for example - at least here in europe.) BUT: There is the huge problem of the plastic knobs (for the locks and so on). These are quite bad and they are breaking quite easy. At least at the beginning that was a HUGE problem. So it´s recommended to get sprae parts already when you buy the head. But that´s it (problem wise). At least as far as I know.

Btw.: I am also already at 5 or 6kg with the rig. And it annoys me because full loaded it will be easily over 8 or 9kg (for a DSLR / SYSTEM CAMERA rig !?!). I think I will reduce / sell my rig and make a more usable setup - Handheld (as lightweight as possible) and tripod (as minimalistic and easy to use as possible). So you also don´t need the most espensive tripod (+ head). ^^

Also an option and this is what I will get (as soon as possible): The Benro H8 head + a A373T tripod (single tube aluminium version). It´s not that expensive (around 600 to 700€ incl. VAT for the WHOLE KIT - full name A373TH8). Because: I already used / had the H10 head + the A674T tripod for a few weeks - REALLY good head for the price (and I used it with a 10,5kg rig / camera of a friend - Without ANY problems - also not counterbalance wise.) Silky smooth operation, 5 years warranty (if you get it from the official dealer) and a very stable head (btw. - Cartoni is also offering 5 years of warranty if that one is more interesting for you ^^). About the H10 kit additionaly: Only the weight was a little bit too high (of the legs primarily). And the legs weren´t the most comfortable ones (especially to unfold - and I don´t like ground spider tripods). It´s way easier & more comfortable to use the single tube legs (like the A373T of the A373TH8 kit). And such a tripod is also very nice to use for stills photography (with a 75mm flat base adapter + a ballhead or geared head for example).

Ok. That´s it. Sorry for the long text. Hope that helps ^^.

thanks guys for the response. i understand the tripods i mentioned are suited to the larger end of my spectrum. I guess i am more concerned with getting a tripod that works really well when my rig is fully loaded. (9 kg) it would be nice for it to do the range but i think maybe thats asking too much? (i could always get something for the lower range as well for the rare occasions i go barebones lightweight like a weifeng 718 because when its lightweight more often than not the case is its not a task were absolute quality is paramount... but it would be better if i could find something to cover from 0 to 10 kg well admittedly ) .

@Vitaliy_Kiselev I was also very interested in the FC-04H in deals how would it with the heavier spring installed handle and counterbalance effectively a 10kg rig ? @Tscheckoff thanks for all the info i will look into both, what weights would you say the h8 will handle from and too? (is the h10 the lower model or the model above? )

it is rare for me not to at least wack the gh3 with manual glass on a minimum of a 2.24kg cage rails follow focus and evf amounting to 4kg.

thanks again , sorry for my ill informed and undereducated questions - still very much learning and enjoying absorbing all the info i can get.

About the cage + weight on top: Good tip. But not helping that much (if you want to mount a 1 up to 2 kg camera system to a head with a spring system for 5kg or 6kg at the lower end).

You arenot fully right here. If you open any counterbalance chart you'll see how much smaller weight must be if center of mass is higher :-) It is just physics.

@Tscheckoff that may be what i end up doing , keeping the ace m spare in the bag / cupboard for when the occasion calls to go ultra light.

how exactly do you work out your rigs G.O.G anyone?