I don't under stand the hysteria with Pukani and PO4. I know it has it and needs to be removed but it's not that bad, really. I added 50 pounds of dry Pukani right into my existing system, dropped it all right into the sump. There was a small algae bloom on its surface when I added it to the display a month after being in the sump but that algae was gone a month after that.
I would use LC (PhosphateRX) while your are cycling. Add as much as you need to keep it zero. Keeping it that low will pull more PO4 from the rock and into the water via equilibrium process. No water changes until fully cycled. Do a big water change then and add your cheato. Do some organic carbon dosing (NOPOX, vinegar, vodka, sugar, whatever), run a little GFO, and do your water changes.
You will have some algae no matter what being a new system starting out. Just keep your PO4 low, of you see algae growing you have too much PO4, even if your tests say zero. Just be aggressive now before you add corals for the first weeks or months. Can have fish but hold off on coral until you have the PO4/algae under control. Also keep your skimmer going now and throughout.
I haven't ever had a problem with PO4 despite starting with 100 pounds of new dry Pukani. I currently use all the following, skimmer, very large fuge and high power grow light, BRS high capacity GFO, every 1/2 hour add 2ml mix of vinegar sugar, grazers (Tangs and snails but PODS do most of it believe it or not), and large water changes. It's not necessary to use all these methods but I prefer to use a little of everything. First of all they have many more purposes than just PO4 control, secondly using a little of each prevents sudden swings up or down and I've completely cured the Pukani long ago.
The benefit of cycling while riding your rock of PO4 now is you kill two birds one stone, and now before adding livestock you can and should be aggressive. Use as much LC and GFO as needed, everyday. Of your worried about the LC not removing the PO4 completely from the system run filter socks, skim wet, and it's ok you do some water changes but I don't really see the benefit until your cycle is completed. LC (phosphateRX) binds up the PO4 so it doesn't actually get removed from the system. It's possible some is removed via skimming and very fine filter socks so if your are worried about that use lots of BRS high capacity GFO.