Here we go Ivan, hope this makes some sense!
Unfortunately, the D8 has no ‘perfect’ set up in the way of drivetrain, thanks to the 68mm BB and the stupidly wide swing arm. No matter what you do, there will always be some compromise in the system; the best you can do is just minimise it.
As you know, I started off following your steps almost to the letter, with the half e.13 on the bottom, and a ghetto piece of plastic bolted to the top. This system worked very well, in fact, I would go so far as to say it was better than that of the complete SRS I’d been running on the old frame. I did the same as you, and spaced out the top plate slightly to keep it closer to the chain ring. After running this for a while, I developed the intelligent idea of turning it into a dodgy LG1 style system. This worked as well, but relied entirely on a zip tie holding the guide at the right angle.
As you know my D8 was looking pretty shitty, and needed a breath of fresh life, so all the ghetto bits and bobs were ditched, and I went in search of a chain guide to fit. My search pulled up two possible contenders, the e.13 SRS+, and the Gamut P30. My first choice was the Gamut, but my LBS happened to have the e.13 in stock at the time, so it was quicker and less painful.
Now, as far as the main pivot bolt up system is on yours, there may be slight complications. To maximise clearance, and minimise headaches I flipped the main pivot bolt around, so the flat head was on the drivetrain side. I am not 100% as to how the frame was assembled from factory, so this may well be the way yours is, if that is the case, ignore this. I did some very slightly ghetto stuff with mine in the way of two 4mm spacers, one on each side, and pressing the bearings to the very outer edges of the swing arm. I then used the standard 6mm bolt with two washers underneath (in a step up style).
So, onto how the drivetrain was set up. Originally, I had it set up with the ISCG plate flat against the frame (with the recessed part facing outwards) with two of the 2.5mm spacers in between that and the BB. This worked great for a few weeks, but my drive side BB kept undoing itself, and I couldn’t work out why. Then, one weekend it came loose again, and as I pulled the crank and spindle out to tighten it, the whole cup came with it, complete with destroyed threads. Fuck.
After much swearing, head scratching and tearful looks a conclusion was reached. First off, one of the 2.5mm spacers was ditched, and so was the plastic sleeve that connects the two cups. I Placed the ISCG adaptor against the frame, the same way it was to begin with, with one 2.5mm spacer in between that and the BB. On the non drive side I ran no spacers. I then installed the e.13 using one set of the 2.5mm (black) spacers. The final step was to use a 5mm headset spacer in between the crank arm and the BB face. This wasn’t the ideal solution, but I had limited choices in the middle of nowhere. As it happens, this worked really well, and still don’t have any problems, but if you were to do it, I would use a proper spindle spacer.
All of this does put the chain line slightly out, and I do get some rubbing on the lower guide in the lowest few gears, but it’s not too bad. If you really want the e.13, do it, but if you aren’t too fussed, and your current set up works, don’t fiddle.
I hope all that helped, and if you do end up giving it a go or just have any more questions, give me a yell and I’ll do my best to help you out. I will get some photos of the set up tomorrow when Mr. Sun comes back up.
