I have been looking at a way to get a Yagi on my roof. No room for a big tower at my QTH, but something on the roof is within reason. I have been looking at the Glen Martin Roof Towers, particularly the smaller Glen Martin RT-424 Roof Tower. It is a 4.5 foot tall, four-legged “quad pod.” The prices on these have suddenly been reduced substantially, so I finally placed an order.
I received the package a couple days ago. Today I decided to put it together. It is a lousy day here anyway, so I will build it in the garage. The box was surprisingly small. They did a good packaging job. Just a bunch of pieces of machined aluminum, a shrink-wrapped container of hardware and a 4-page manual.
Looking at reviews on eHam, it appears to be a good quality item, with not-so-great instructions. With a couple pictures in the manual, it looks like is should be fairly easy to build.
I will post some of my findings as I put it together. Hopefully everything I need is there. I still need to find a rotor for the rooftop setup. The antenna will be a used C3S 10/15/20 meter yagi that I bought a few months ago. This will be the first yagi I have had in a station for many years, so it should be fun.
Kg3v Ham Radio Blog 
You were very lucky. In Dec. 2019 I ordered a SP7IDX Industries 6 band hexbeam antenna from the one-man manufacturer in Poland. After months of research, it seemed to be the hexbeam with the best materials used in the design. I then researched a roof-top tower on which to mount it. The one that drew my attention was the Glen Martin RT-424. Since I knew there was a large lead time for the antenna (he told me before ordering that it would take him at least 6 weeks just to get to me), I didn’t want to order the tower until I had the antenna. Well, after the 6 weeks had passed, Waldi (SP7IDX) notified me he had finished my antenna construction, but that he couldn’t send it to me due to Covid restrictions in eastern Europe regarding package deliveries to the USA. To make a long story short, I didn’t get the antenna until the middle of June. Then I went back to the Glen Martin website to order the tower. Much to my chagrin, I found that Glen Martin had apparently gone out of business, as no one answered my emails and the phone number shown on their website had been disconnected. What a quandry! Then, I found a company on line that was still operating that sold metal on the web. They had the same grade of aluminum used in the Glen Martin tower. I had previously downloaded the instruction sheet you mentioned. I ordered the metal angles to construct the tower. After two months, I finally had a tower built from the parts I had ordered and put it up on my roof and installed the antenna.