Money = weight, or lack thereof in the tripod game. The reality is however you're saving a couple of pounds total overall - that's important to some - not others.
As has been said - be very mindful of the weight carrying capability of not only the tripod, but also the ballhead too. Bat strong on these as the weights are for cameras with largely central centre of gravities, not long rifles. On the tripod, the legs need to be as tall as possible, so you don't have to use much if any of the central column - a short centre column should also allow you to go prone should you need. Also ensure therefore that the spread of the feet of the tripod is as wide as possible for overall stability, especially on uneven surfaces and when there is a breeze about.
The saddle you've been shown is the Hog Saddle from the cost - c.£300. Their Pig saddle, the Triclawps and others are around £140. I made my first one out of some sheet steel that I bent to create a compression fit, lined with bicycle inner tube and bolted an Arca clamp on. Took me about 40 min, including painting it - and it was fine - albeit only any good for one rifle.
The other alternative is to connect the Arca Swiss plate direct to your rifles - at <£10 each, it's not a big outlay. Buy ones at least 70mm long.
Ball head - try for one with as large a ball in it as possible - more surface to grip and gives a smoother pan. Expect to pay c.£50 odd for a good one that will manage 15-20kg of camera - up to £300 plus for a name.
So you're at £200 (if you buy a branded clamp) - the Wicked Rekon is £400 all in, which means you're getting a carbon tripod for about £200. That's pretty good. Tripods should have no more than four sections per leg, or they're just too flimsy - three sections best. Remember height as some just wont get tall enough - the leg spread sort of comes naturally with these. If you look on the Bay for a Slik Pro DX tripod you won't go far wrong for aluminium. Carbon is more difficult and I'd look for Giottos, Manfrotto or Gitzo. There's a G1228 on there for £190 ATM which is a fine tripod.
Getting a set up and working with it is worth the effort. It is the most agile of all systems in terms of being able to cope with all environments and terrains, just as quick to deploy with practice and incredibly stable - sub MOA at 800m standing.
