SRT is great for bigger trees. I don't get a lot of bigger trees, but when i do it's worth the switch over. All SRT systems are good, it's more a matter of which one you're proficient with. The wrench, like any system has its pros and cons.
I think most residential tree guys could benefit more from spruicing up there normal working techniques. A good foot ascender plus a slack tender takes most of the work out of ascending in the sub 80 foot range. The pantene kicks out too easy for my liking, and I'm a petzl nut from way back. I use the CMI foot ascender. It's ugly as sin and about the size of a russian tank, but it engages positively and never kicks out.
I use a small u shaped shackle plus a loop of zing it for my slack tender. I'll photograph the setup sometime this week if anyone's interested. It cost me about $6. The U shaped shackle has a captive pin so you can't drop it, and the zing it loop acts as a prussik. It's tied to the shackle in such a way that the shackle cant come off. I attach the zing it 'prussik' to the harness side of my climb line. The shackle clips on under my hitch. You can slide the prusik up or down to set it right for no set back. When you're in the tree, one of the biggest pains of a slack tender system is that you can't easily give yourself slack when you need it. The advantage of this system is that you can unclip the shackle in about 1 second.
The slack tender saves a lot of work, but the real benefit is with having it together with the foot ascender. With a normal hitch system you can only hump air equal to the distance of about one prusik loop length. ie. if your prussik loop is 18", the hitch ends up at about waist height with each 'hump' and you slide it up. You don't see guys humping to the point the hitch ends up at their knee. If you use a foot ascender without a slack tender, you can only take 'steps' equal to your hitch length. Because it's hard to slide the prusik up from your knee. With the slack tender, the hitch never drops. So you can take steps as big as you want, easily as big as two full size 'humps'. The effort is a lot less, none of it is wasted. Yeah, you're still only getting half your height out of each go, but it's so easy and smooth.
For long ascents, you can add a single ascender and footloop plus a bit of shock cord for a texas rope walked styled ascent. Coupled with the $6 slack tender it's a hard system to beat. I use it for medium trees (up to about 100' freehanging ascent). It already uses the hitch that we all know and love and is great for working the tree. The foot ascender is pretty transparent and good to have on for working the tree. I set my high point with a big shot, setup the ascender. Tie my hitch and get moving. It's pretty effortless, and you can get to 110' and not be out of breath. I say this as a big fat bastard. At that point I usually send the ascender down and the only extra bit of gear I'm carrying is the foot ascender which is good for working the tree. This is really only for pruning work, on a removal I'm going spikes all the way.
Will take pics/vids if anybody is interested.
Shaun
