I maintain that I am not one for spending money on gap filler kits. They tend to cost too much for what they are and do, and for the most part I'm not bothered by some visible bits like that. But I made an exception in this case.
I recently got a good deal on a Kingdom Magnus (two right missiles -- anyone have a spare left one?), figuring it would do for now while I wait for one with a better altmode. (Who knows when that'll be.) Had trouble getting past the un-unseeable gaps in the shoulder posts, as every time you want to look at him head-on, they're right there, these weirdly hollow posts with shelves in them. And solid shoulder posts have always been part of the Magnus "look" (especially relevant for a figure whose design meant to evoke it so directly)... so this felt like a more justifiable fix than "oh, this random bot's inner forearms have an empty space and some ridges".
In the end I found the Ratchet Operating Studio kit, one of those mass 3D printed clusters of gap fillers making the rounds on ebay and elsewhere, and figured ~$15 was a good price for a few usable pieces (with the rest going to resale to recoup costs). I noticed that upper-leg extensions were part of the kit, as well as a 5mm peg that would allow the rifle to be attached to the back, so it seemed like an even better deal. The leg extensions weren't the priority, but they certainly sweetened the pot.
On the whole it's... All right. These extensions show that there's really only so much to be done with the mold to deal with the legs. They move the mushroom pegs a smidge above where they were, probably because right above the tops of the original upper legs seems like the only other place you could put a mushroom joint slot.
(I assume, at least. I guess it's possible to make something that sandwiches the mushroom joint and fits within the original thigh? Hell, I guess you could just make a new slightly longer upper leg since the lower legs SEEM to disassemble easily enough for a replacement?)
(Obligatory: you do need to shave down the original mushroom pegs a teeny bit to retain the articulation and make the swivel less scary-tight.)
As such, now the arms seem a BIT short, mostly due to the short biceps/high elbows. The colors contribute to it as well, with the mostly white boot fronts (Siege had the side walls in blue). Also, the minimal blue on the belt/groin piece (because the hinged bit below needs to be white for unarmored mode) adds to the "the legs start too high up" vibe.
It doesn't look TOO bad, but it reminds me of Dream Huey from some angles.
Unarmored Magnus looks good. With slightly shorter legs due to the lack of big boots, the arm/leg proportion issue is less striking, but still there -- and the head now looks pretty small. On the plus side, the width (brought by his truck front 1:1 being his torso front). no longer makes him look short and dumpy. Thanks to the added height, now he comes across as a stocky powerhouse.
The height also helps distribute the armored mode's chunkiness and mass better -- the short legs put the immense backpack too close to the also-chonk legs, which is now less of an issue. Now he can look armored without looking burdened by it.
On the whole, not bad. I wish there were an option to get just these parts, but the price is right (especially if someone more into gap fillers is willing to buy the rest off you). It's quite a bit cheaper than most other options, and I've not heard encouraging things about the pricier kits either.
I may also be overstating the arm/leg proportion situation (thoughts?), as it liekly just takes some getting used to. Mainly, though, I really can't complain about how well the shoulder things turned out; that was worth breaking that self-imposed rule.
Funny enough, I still have the original problem I had with regard to the missiles, but we'll see where we go from here.