primary /secondary radiant loop

[802 vt]

Hello I am new here and have a question on primary /secondary loop I have two separate radiant loops 3 loops each around 200 feet each...they both have their own circulator and were hand built manifolds ,these are installed in a small utility room 50 feet from the boiler . At the time the boiler was a older smith and has since been replaced with a well mclain gv5 ,I am replacing these secondary loops with abst 3 loop manifolds .I have done this myself and wanted to make sure this is correct plumbing. These radiant loops were built with a crossover between supply and return with a valve partially cracked open ,I made a header with closely spaced tees feeding this secondary loop ,the supply and return 90 into these tees opposed to branching off of supply and return lines ,all this is 3/4 inch piping..is this correct? or do i need to change anything ..I believe I managed to provide a photo any feedback would be greatly appreciated..Thanks