Installing Replacement Anti-Siphon Valve

First I'll remove the old valve by cutting the pipes, then glue on new

3/4" PVC pipes to get the new valve well above ground level. Then screw 3/4" fittings into the female openings of the valve. NOW, HERE'S THE QUESTION: it seems difficult to get the fittings onto the pipes because twisting is impossible. Do you just put on a lot of blue glue and quickly shove both sides (valve and antisiphon) on? Twisting is supposed to give a better seal. One way I thought of is apply the glue in all 8 places (both sides of each pipe and all 4 fittings (2 for the extension and the 2 in the valve unit), have a helper push down on the valve unit while I hold the extension pipes, one in each hand, and twist them both into their top and bottom fittings at the same time. And we get only one chance to get it right. Advice appreciated.

I just looked at one I had done several years ago. Looks like my two pipes screwed into the anti-siphon valve. I attached a male/slip fitting to each pipe and put them into the anti-siphon valve, tightening most but not all of the way. Then I used a slip fitting on the receiving end. Put solvent/cleaner on the loose ends and attached the whole apparatus. With the slip ends of the piping inserted I could tighten the threaded ends and rotate the slip ends simultaneously.

Alternatively you can just use a lot of solvent in the hopes that the excess helps to bridge any gaps that screwing would have mended. Or you could use Union pieces, although they're a little more expensive. The union would allow you to disassemble if you need to replace it.

Another technique is to assemble the whole unit in advance with elbows at the bottom of the pipes emanating from the valves and then bend them slightly to fit in to the main pipes.

Just ideas off top of my head.

Tim