My DK35SE HST with R4's seems similar to yours Powerscol. I have just 2" clearance between the sidewall and ROPS frame running up the inside tire well. I had to keep the chains high on the tire to make them work. I managed to fit heavy DUO chains by modifying the end connections (had to use two ladder cross chains to close the end gap) and using tensioners. They worked with no problems for two years. However, the DUO pattern, which skips a link between patterns, was very rough. Also, the end-gap ladder cross chains tended to shift into the tread over time resulting in an even rougher ride and some slippage under load.
The chains worked well but had to be installed "just right". So I decided to modify my DUO's to the H-pattern like the ones you have. That made a huge difference due to the H-pattern's not skipping a link as DUO's do. The tighter pattern made the chains ride higher on the tire wall, and I only needed one ladder chain instead of two at the end gap. Of course that ladder cross chain still eventually managed to disappear in the tread over time. The details are in this thread:
http://www.tractorbynet.com/forums/...ed-modifications-post3150916.html#post3150916
A year later I fixed the troublesome ladder cross chain at the end gap by adding one more DUO pattern that gap as shown here:
http://www.tractorbynet.com/forums/...ed-modifications-post4045498.html#post4045498
I found the pin couplers shown in the link to be easier to work with than other types of links.
I think your chains will work fine. I have not had any trouble with my chains fairly high on the sidewall. Since you have a chain tool it should not take that long to build the chains. Looking through the referenced thread, I see it took me 4 hours to modify my DUO's to the H-pattern. Also, I ordered a continuous length of DUO patterns to make the H-pattern (it was much cheaper than buying single patterns). I had to completely disassemble my existing DUO's plus the additional DUO patterns before building the H-pattern chains. And the DUO's are 9mm instead of H-pattern's 7mm.
If possible, span the end gap with an H-pattern rather than leaving any unfilled gaps. That is, close the side chain normally, but have an H-pattern span that gap to a link in the H-pattern on the opposite side. I found it eliminates potential problems with the chain shifting at the end gap. I have 1 twisted link in the cross-hook and connect the gap-spanning H-pattern to it with the pin coupler. The closing side of the last H-pattern has two less links than other patterns, one of which is in the cross-hook to which the closing pattern connects, and the other is replaced with the pin coupler connecting that single link in the cross-hook and H-pattern together.
If you need to lengthen the end gap so a pattern fits across it correctly, one option is to replace some of the long side chain links with shorter pin couplers , or use the other type with two halves and pins that you pound to lock the two halves together, or the other type that are one piece and squeeze together.
As for mounting chains; I had trouble with a cable over the tread slipping off. Instead I lift the end of the chain to the top of the tire and hold it while my wife presses the HST forward pedal to roll the rest of the chain on the tire. When the front part of the chain is almost to the ground, I spread the chain across the tread as best I can and connect a bungee on the inside from the side chain (that is almost hitting the ground) to the back side chain, that is still coming up the back side of the tire. Then roll ahead again and drive over the front part of the chain after it hits the ground until you are over it and there is a foot or two extending on the ground to the back of the tire. The other end will now be off the ground hanging down the rear of the tire. Distribute everything as best you can on the tread and connect the inside hook. Then connect the outside closing lever, but you likely cannot close it. Move the tractor a bit more so you can distribute and straighten the still fairly loose chain. You should then be able to close the outside lever. Once the chain is mounted drive back and forth a bit, stopping to distribute and straighten it. I did buy one of those closing load-binder things but have never used it.
Then put on tensioners if you need them. I need them on the rear chains but not on the fronts. I made the ones shown here for my rear tires:
http://www.tractorbynet.com/forums/tires/299418-tire-chain-tensioners-post3588210.html#post3588210
..... because I had all the parts from tearing apart the bulk DUO patterns. The photo in this thread was before I figured out closing the end gap with an H-pattern. Now I just use three tensioners instead of six.
You have all the pieces so it should not be too hard to start building one chain and see how it fits. It may be a good idea to squeeze things just enough so you can test the chain and it is not too hard to get it apart if you decide you need to shorten the cross pattern.