To answer point one, the DeWalt and I believe Delta are the triangle shape. The Pegas has four bolts to fasten to the stand. I would recommend the rectangular one for the Pegas.
I am out of stock of Pegas #2/0R MGT and almost out of stock of Pegas #1R MGT blades in the dozen pack (Pegas backorder). Plenty of stock on the 12 dozen/pack. If you need the dozen pack, send me a message.
I would be happy to help with any Pegas order. I usually get the orders out the next day. If you have any questions message me. The link to the website is on the signature.
As a Pegas dealer, yes, Seyco does service Pegas scroll saws. but does not have access to Pegas parts. This is a consideration if the saw is under warrantee.
For years I used FD UR and Polar blades. Now that we are a Pegas dealer. I use mostly MGT in sizes #1 through #5. I do use #7 MGT for compound cutting.